diff --git a/ROADMAP.md b/ROADMAP.md
index 011ef65..a484a05 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -150,7 +150,7 @@
 - [X] "no-native-reassign"
 - [ ] "no-negated-condition"
 - [X] "no-negated-in-lhs"
-- [ ] "no-nested-ternary"
+- [X] "no-nested-ternary"
 - [ ] "no-new"
 - [ ] "no-new-func"
 - [ ] "no-new-object"
diff --git a/src/rules/default.json b/src/rules/default.json
index dd4523a..dc3a90a 100644
--- a/src/rules/default.json
+++ b/src/rules/default.json
@@ -227,6 +227,9 @@
   "no-negated-in-lhs": [
     "off"
   ],
+  "no-nested-ternary": [
+    "error"
+  ],
   "no-spaced-func": [
     "off"
   ],