diff --git a/biology/prodigy-lig/Makefile b/biology/prodigy-lig/Makefile
index ccc9c5f32df7..cedcf9883503 100644
--- a/biology/prodigy-lig/Makefile
+++ b/biology/prodigy-lig/Makefile
@@ -16,7 +16,7 @@ LICENSE_FILE=	${WRKSRC}/LICENSE
 BUILD_DEPENDS=	${PYNUMPY} \
 		${PYTHON_PKGNAMEPREFIX}biopython>0:biology/py-biopython@${PY_FLAVOR}
 
-USES=		gmake python:3.5+
+USES=		gmake python:3.6+
 USE_GITHUB=	yes
 GH_ACCOUNT=	haddocking
 USE_PYTHON=	distutils noflavors autoplist
diff --git a/science/py-MDAnalysis/Makefile b/science/py-MDAnalysis/Makefile
index 2773a422fc1d..2aa98aa5555e 100644
--- a/science/py-MDAnalysis/Makefile
+++ b/science/py-MDAnalysis/Makefile
@@ -27,7 +27,7 @@ RUN_DEPENDS=	${PYNUMPY} \
 		${PYTHON_PKGNAMEPREFIX}scipy>=1.0.0:science/py-scipy@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}six>=1.4.0:devel/py-six@${PY_FLAVOR}
 
-USES=		compiler:c++11-lang python
+USES=		compiler:c++11-lang python:3.6+
 USE_PYTHON=	distutils autoplist
 
 .include <bsd.port.mk>
diff --git a/science/py-MDAnalysisTests/Makefile b/science/py-MDAnalysisTests/Makefile
index 5abb954bc83a..1f409fb05898 100644
--- a/science/py-MDAnalysisTests/Makefile
+++ b/science/py-MDAnalysisTests/Makefile
@@ -20,7 +20,7 @@ RUN_DEPENDS=	${PYNUMPY} \
 		${PYTHON_PKGNAMEPREFIX}psutil>=4.0.2:sysutils/py-psutil@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}mock>=2.0.0:devel/py-mock@${PY_FLAVOR}
 
-USES=		python
+USES=		python:3.6+
 USE_PYTHON=	distutils autoplist
 NO_ARCH=	yes