diff --git a/packages/casl-ability/spec/rulesToAST.spec.js b/packages/casl-ability/spec/rulesToAST.spec.js
index 9868d0062..e60062d48 100644
--- a/packages/casl-ability/spec/rulesToAST.spec.js
+++ b/packages/casl-ability/spec/rulesToAST.spec.js
@@ -44,7 +44,12 @@ describe('rulesToAST', () => {
     expect(ast).to.deep.equal({
       operator: 'and',
       value: [
-        { operator: 'eq', field: 'private', value: true },
+        {
+          operator: 'not',
+          value: [
+            { operator: 'eq', field: 'private', value: true }
+          ]
+        },
         {
           operator: 'or',
           value: [
diff --git a/packages/casl-ability/src/extra.ts b/packages/casl-ability/src/extra.ts
index b70a1f079..2ed93b82e 100644
--- a/packages/casl-ability/src/extra.ts
+++ b/packages/casl-ability/src/extra.ts
@@ -1,4 +1,4 @@
-import { Condition, buildAnd, buildOr } from '@ucast/mongo2js';
+import { Condition, buildAnd, buildOr, CompoundCondition } from '@ucast/mongo2js';
 import { PureAbility, AnyAbility } from './PureAbility';
 import { RuleOf } from './RuleIndex';
 import { RawRule } from './RawRule';
@@ -45,7 +45,8 @@ function ruleToAST(rule: RuleOf<AnyAbility>): Condition {
   if (!rule.ast) {
     throw new Error(`Ability rule "${JSON.stringify(rule)}" does not have "ast" property. So, cannot be used to generate AST`);
   }
-  return rule.ast;
+
+  return rule.inverted ? new CompoundCondition('not', [rule.ast]) : rule.ast;
 }
 
 export function rulesToAST<T extends AnyAbility>(