diff --git a/accounts/abi/pack_test.go b/accounts/abi/pack_test.go
index 0fb93856d90d..5f802fce07a5 100644
--- a/accounts/abi/pack_test.go
+++ b/accounts/abi/pack_test.go
@@ -42,7 +42,7 @@ func TestPack(t *testing.T) {
 		{
 			"uint8[]",
 			[]uint8{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"uint16",
@@ -52,7 +52,7 @@ func TestPack(t *testing.T) {
 		{
 			"uint16[]",
 			[]uint16{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"uint32",
@@ -62,7 +62,7 @@ func TestPack(t *testing.T) {
 		{
 			"uint32[]",
 			[]uint32{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"uint64",
@@ -72,7 +72,7 @@ func TestPack(t *testing.T) {
 		{
 			"uint64[]",
 			[]uint64{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"uint256",
@@ -82,7 +82,7 @@ func TestPack(t *testing.T) {
 		{
 			"uint256[]",
 			[]*big.Int{big.NewInt(1), big.NewInt(2)},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"int8",
@@ -92,7 +92,7 @@ func TestPack(t *testing.T) {
 		{
 			"int8[]",
 			[]int8{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"int16",
@@ -102,7 +102,7 @@ func TestPack(t *testing.T) {
 		{
 			"int16[]",
 			[]int16{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"int32",
@@ -112,7 +112,7 @@ func TestPack(t *testing.T) {
 		{
 			"int32[]",
 			[]int32{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"int64",
@@ -122,7 +122,7 @@ func TestPack(t *testing.T) {
 		{
 			"int64[]",
 			[]int64{1, 2},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"int256",
@@ -132,7 +132,7 @@ func TestPack(t *testing.T) {
 		{
 			"int256[]",
 			[]*big.Int{big.NewInt(1), big.NewInt(2)},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002"),
 		},
 		{
 			"bytes1",
@@ -308,12 +308,18 @@ func TestPack(t *testing.T) {
 			//web3.eth.abi.encodeParameter('address[]', ['0x0100000000000000000000000000000000000000','0x0200000000000000000000000000000000000000']);
 			"address[]",
 			[]common.Address{{1}, {2}},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000200000000000000000000000001000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020" +
+				"0000000000000000000000000000000000000000000000000000000000000002" +
+				"0000000000000000000000000100000000000000000000000000000000000000" +
+				"0000000000000000000000000200000000000000000000000000000000000000"),
 		},
 		{
 			"bytes32[]",
 			[]common.Hash{{1}, {2}},
-			common.Hex2Bytes("000000000000000000000000000000000000000000000000000000000000000201000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020" + //offset: 32
+				"0000000000000000000000000000000000000000000000000000000000000002" + //len: 2
+				"0100000000000000000000000000000000000000000000000000000000000000" + // 1
+				"0200000000000000000000000000000000000000000000000000000000000000"), // 2
 		},
 		{
 			"function",
@@ -323,12 +329,15 @@ func TestPack(t *testing.T) {
 		{
 			"string",
 			"foobar",
-			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000006666f6f6261720000000000000000000000000000000000000000000000000000"),
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020" + // offset: 32
+				"0000000000000000000000000000000000000000000000000000000000000006" + // len: 6
+				"666f6f6261720000000000000000000000000000000000000000000000000000"), // "foobar"
 		},
 		{
 			"string[]",
 			[]string{"hello", "foobar"},
-			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002" + // len(array) = 2
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020" + // offset array 32
+				"0000000000000000000000000000000000000000000000000000000000000002" + // len(array) = 2
 				"0000000000000000000000000000000000000000000000000000000000000040" + // offset 64 to i=0
 				"0000000000000000000000000000000000000000000000000000000000000080" + // offset 128 to i=1
 				"0000000000000000000000000000000000000000000000000000000000000005" + // len(str[0]) = 5
@@ -343,7 +352,8 @@ func TestPack(t *testing.T) {
 			// '0x0400000000000000000000000000000000000000000000000000000000000000','0x0500000000000000000000000000000000000000000000000000000000000000']]);
 			"bytes32[][]",
 			[][]common.Hash{{{1}, {2}}, {{3}, {4}, {5}}},
-			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000002" + // len(array) = 2
+			common.Hex2Bytes("0000000000000000000000000000000000000000000000000000000000000020" + // offset array 32
+				"0000000000000000000000000000000000000000000000000000000000000002" + // len(array) = 2
 				"0000000000000000000000000000000000000000000000000000000000000040" + // offset 64 to i=0
 				"00000000000000000000000000000000000000000000000000000000000000a0" + // offset 160 to i=1
 				"0000000000000000000000000000000000000000000000000000000000000002" + // len(array[0]) = 2
diff --git a/accounts/abi/type.go b/accounts/abi/type.go
index eeb42e7d7c05..dce89d2b4ee4 100644
--- a/accounts/abi/type.go
+++ b/accounts/abi/type.go
@@ -183,43 +183,23 @@ func (t Type) pack(v reflect.Value) ([]byte, error) {
 		return nil, err
 	}
 
-	switch t.T {
-	case SliceTy, ArrayTy:
-		var ret []byte
+	if t.T == SliceTy || t.T == ArrayTy {
+		var packed []byte
 
-		if t.requiresLengthPrefix() {
-			// append length
-			ret = append(ret, packNum(reflect.ValueOf(v.Len()))...)
-		}
-
-		// calculate offset if any
-		offset := 0
-		offsetReq := t.Elem.requiresLengthPrefix()
-		if offsetReq {
-			offset = getOffset(*t.Elem) * v.Len()
-		}
-
-		var tail []byte
 		for i := 0; i < v.Len(); i++ {
 			val, err := t.Elem.pack(v.Index(i))
 			if err != nil {
 				return nil, err
 			}
-
-			if !offsetReq {
-				ret = append(ret, val...)
-				continue
-			}
-
-			ret = append(ret, packNum(reflect.ValueOf(offset))...)
-			offset += len(val)
-			tail = append(tail, val...)
+			packed = append(packed, val...)
+		}
+		if t.T == SliceTy {
+			return packBytesSlice(packed, v.Len()), nil
+		} else if t.T == ArrayTy {
+			return packed, nil
 		}
-
-		return append(ret, tail...), nil
-	default:
-		return packElement(t, v), nil
 	}
+	return packElement(t, v), nil
 }
 
 // requireLengthPrefix returns whether the type requires any sort of length
@@ -227,12 +207,3 @@ func (t Type) pack(v reflect.Value) ([]byte, error) {
 func (t Type) requiresLengthPrefix() bool {
 	return t.T == StringTy || t.T == BytesTy || t.T == SliceTy
 }
-
-// getOffset returns the offset to be added for t
-func getOffset(t Type) int {
-	if t.T == ArrayTy {
-		return 32 * t.Size
-	}
-
-	return 32
-}