diff --git a/package.json b/package.json
index 8225b978..1f7e7ab0 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
     "cross-env": "^5.0.5",
     "cross-spawn": "^5.1.0",
     "css-loader": "^0.28.7",
-    "cssnano": "^3.10.0",
+    "cssnano": "^6.0.0",
     "eslint": "^4.9.0",
     "eslint-config-standard": "^10.2.1",
     "eslint-friendly-formatter": "^3.0.0",