diff --git a/requirements.txt b/requirements.txt
index c4c176c..b1b05cf 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ h5py==2.7.1
 mypy-protobuf==1.3
 numpy==1.14.3
 pandas==0.22.0
-protobuf==3.5.2.post1
+protobuf==3.18.3
 pysam==0.14.1
 python-dateutil==2.7.2
 pytz==2018.4