diff --git a/sci-libs/chemkit/chemkit-0.1-r2.ebuild b/sci-libs/chemkit/chemkit-0.1-r2.ebuild
index 41bd24f09bf8d..c1cb99bc94559 100644
--- a/sci-libs/chemkit/chemkit-0.1-r2.ebuild
+++ b/sci-libs/chemkit/chemkit-0.1-r2.ebuild
@@ -21,7 +21,7 @@ REQUIRED_USE="${PYTHON_REQUIRED_USE}
 
 RDEPEND="
 	dev-cpp/eigen:3
-	dev-libs/boost
+	dev-libs/boost:=
 	dev-libs/rapidxml
 	media-libs/glu
 	sci-libs/inchi