diff --git a/pkgs/development/python-modules/pysam/default.nix b/pkgs/development/python-modules/pysam/default.nix
index 2f65aa899e39..d8a38dff9084 100644
--- a/pkgs/development/python-modules/pysam/default.nix
+++ b/pkgs/development/python-modules/pysam/default.nix
@@ -15,7 +15,7 @@
 
 buildPythonPackage rec {
   pname   = "pysam";
-  version = "0.18.0";
+  version = "0.19.1";
 
   # Fetching from GitHub instead of PyPi cause the 0.13 src release on PyPi is
   # missing some files which cause test failures.
@@ -23,8 +23,8 @@ buildPythonPackage rec {
   src = fetchFromGitHub {
     owner = "pysam-developers";
     repo = "pysam";
-    rev = "v${version}";
-    sha256 = "042ca27r6634xg2ixgvq1079cp714wmm6ml7bwc1snn0wxxzywfg";
+    rev = "refs/tags/v${version}";
+    sha256 = "sha256-fbvfobffLha1eFatnHvh0tOYcuMRLTmy/BJ9QXFHx2o=";
   };
 
   nativeBuildInputs = [ samtools ];