diff --git a/utils/makefile.python b/utils/makefile.python
index 0ae912b5..eab9b20e 100644
--- a/utils/makefile.python
+++ b/utils/makefile.python
@@ -95,7 +95,13 @@ quiet_cmd_pyinstall = INSTALL   $2
 
 # $2 path to folder with setup.py, this uses pip from pyenv (not OS!)
 quiet_cmd_pyenvinstall = PYENV     install $2
-      cmd_pyenvinstall = $(PY_ENV_BIN)/python -m pip $(PIP_VERBOSE) install -e $2$(PY_SETUP_EXTRAS)
+      cmd_pyenvinstall = \
+	if ! cat $(PY_ENV)/requirements.sha256 2>/dev/null | sha256sum --check --status 2>/dev/null; then \
+		$(PY_ENV_BIN)/python -m pip $(PIP_VERBOSE) install -e $2$(PY_SETUP_EXTRAS) ;\
+		sha256sum requirements*.txt > $(PY_ENV)/requirements.sha256 ;\
+	else \
+		echo "PYENV     $2 already installed"; \
+	fi
 
 # Uninstall the package.  Since pip does not uninstall the no longer needed
 # depencies (something like autoremove) the depencies remain.