diff --git a/pyproject.toml b/pyproject.toml
index f880135d..061b505c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,7 +15,7 @@ classifiers = [
   "Topic :: Other/Nonlisted Topic",
   "Topic :: Scientific/Engineering",
 ]
-dependencies = ["pymatgen>=2022.10.22", "scikit-image>=0.19.3", "mp-pyrho>=0.3.0", "numpy<=1.23.5"]
+dependencies = ["pymatgen==2023.1.9", "scikit-image>=0.19.3", "mp-pyrho>=0.3.0", "numpy<=1.23.5"]
 description = "Pymatgen extension for defects analysis"
 dynamic = ["version"]
 keywords = ["high-throughput", "automated", "dft", "defects"]