diff --git a/newsfragments/1815.misc.rst b/newsfragments/1815.misc.rst
new file mode 100644
index 0000000000..c62e389dd0
--- /dev/null
+++ b/newsfragments/1815.misc.rst
@@ -0,0 +1 @@
+Remove unused bufsize argument in integration testing setup to fix subprocess's RuntimeWarning
diff --git a/tests/integration/generate_fixtures/common.py b/tests/integration/generate_fixtures/common.py
index fdde519109..fba04ab72d 100644
--- a/tests/integration/generate_fixtures/common.py
+++ b/tests/integration/generate_fixtures/common.py
@@ -190,7 +190,6 @@ def get_process(run_command):
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
-        bufsize=1,
     )
     return proc
 
diff --git a/tests/integration/generate_fixtures/go_ethereum.py b/tests/integration/generate_fixtures/go_ethereum.py
index 6e1ddbddbf..e6cd6197d5 100644
--- a/tests/integration/generate_fixtures/go_ethereum.py
+++ b/tests/integration/generate_fixtures/go_ethereum.py
@@ -82,7 +82,6 @@ def get_geth_process(geth_binary,
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
-        bufsize=1,
     )
     with popen_proc as proc:
         with graceful_kill_on_exit(proc) as graceful_proc:
diff --git a/tests/integration/go_ethereum/conftest.py b/tests/integration/go_ethereum/conftest.py
index 85f3c96838..3063164aa6 100644
--- a/tests/integration/go_ethereum/conftest.py
+++ b/tests/integration/go_ethereum/conftest.py
@@ -113,7 +113,6 @@ def geth_process(geth_binary, datadir, genesis_file, geth_command_arguments):
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
-        bufsize=1,
     )
     try:
         yield proc
diff --git a/tests/integration/parity/utils.py b/tests/integration/parity/utils.py
index 0403533c58..1a594668e0 100644
--- a/tests/integration/parity/utils.py
+++ b/tests/integration/parity/utils.py
@@ -40,7 +40,6 @@ def get_process(command_list, terminates=False):
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
-        bufsize=1,
     )
     if terminates:
         wait_for_popen(proc, 30)