diff --git a/src/main/java/com/netgrif/application/engine/pfql/domain/antlr4/QueryLang.g4 b/src/main/java/com/netgrif/application/engine/pfql/domain/antlr4/QueryLang.g4
index d98dc27bc8..b561bf21b6 100644
--- a/src/main/java/com/netgrif/application/engine/pfql/domain/antlr4/QueryLang.g4
+++ b/src/main/java/com/netgrif/application/engine/pfql/domain/antlr4/QueryLang.g4
@@ -245,7 +245,7 @@ placesComparison: places SPACE numberComparison # placesBasic
                 | places SPACE inRangeNumberComparison # placesRange
                 | places SPACE nullComparison # placesNull
                 ;
-tasksStateComparison: tasksState SPACE (NOT SPACE?)? op=EQ SPACE state=(ENABLED | DISABLED) ;
+tasksStateComparison: tasksState SPACE (NOT SPACE?)? op=(EQ | NEQ) SPACE state=(ENABLED | DISABLED) ;
 tasksUserIdComparison: tasksUserId SPACE stringComparison # tasksUserIdBasic
                      | tasksUserId SPACE inListStringComparison # tasksUserIdList
                      | tasksUserId SPACE nullComparison # tasksUserIdNull
diff --git a/src/main/java/com/netgrif/application/engine/pfql/service/QueryLangEvaluator.java b/src/main/java/com/netgrif/application/engine/pfql/service/QueryLangEvaluator.java
index 7230c30854..b91a87ac99 100644
--- a/src/main/java/com/netgrif/application/engine/pfql/service/QueryLangEvaluator.java
+++ b/src/main/java/com/netgrif/application/engine/pfql/service/QueryLangEvaluator.java
@@ -1489,16 +1489,16 @@ public void exitPlacesRange(QueryLangParser.PlacesRangeContext ctx) {
 
     @Override
     public void exitTasksStateComparison(QueryLangParser.TasksStateComparisonContext ctx) {
-        // todo implement task states
-//        String taskId = ctx.tasksState().taskId.getText();
-//        Token op = ctx.op;
-//        checkOp(ComparisonType.STRING, op);
-//        boolean not = ctx.NOT() != null;
-//        State state = ctx.state.getType() == QueryLangParser.ENABLED ? State.ENABLED : State.DISABLED;
-//
-//        setMongoQuery(ctx, null);
-//        setElasticQuery(ctx, buildElasticQuery("tasks." + taskId + ".state", op.getType(), state.toString(), not));
-//        this.searchWithElastic = true;
+        String transId = ctx.tasksState().taskId.getText();
+        Token op = ctx.op;
+        checkOp(ComparisonType.STRING, op);
+        boolean not = ctx.NOT() != null;
+        boolean isEnabled = ctx.state.getType() == QueryLangParser.ENABLED;
+        boolean taskIsExecutable = isEnabled != not;
+
+        setMongoQuery(ctx, null);
+        setElasticQuery(ctx, buildElasticQuery("taskIds", op.getType(), transId, !taskIsExecutable));
+        this.searchWithElastic = true;
     }
 
     @Override
diff --git a/src/test/java/com/netgrif/application/engine/pfql/QueryLangTest.java b/src/test/java/com/netgrif/application/engine/pfql/QueryLangTest.java
index a9eaf34052..af22111c2d 100644
--- a/src/test/java/com/netgrif/application/engine/pfql/QueryLangTest.java
+++ b/src/test/java/com/netgrif/application/engine/pfql/QueryLangTest.java
@@ -149,6 +149,18 @@ public void testSearchService() throws InterruptedException {
 
         cases = searchService.search("cases: processIdentifier eq 'query_test' and data.text_0.value eq 'x44'*");
         assertEquals(1, ((Page<Case>) cases).getTotalElements());
+
+        cases = searchService.search("cases: processIdentifier eq 'query_test' and tasks.t1.state eq enabled");
+        assertEquals(10, ((Page<Case>) cases).getTotalElements());
+
+        cases = searchService.search("cases: processIdentifier eq 'query_test' and tasks.t1.state eq disabled");
+        assertEquals(0, ((Page<Case>) cases).getTotalElements());
+
+        cases = searchService.search("cases: processIdentifier eq 'query_test' and tasks.t1.state neq disabled");
+        assertEquals(10, ((Page<Case>) cases).getTotalElements());
+
+        cases = searchService.search("cases: processIdentifier eq 'query_test' and tasks.t1.state not eq disabled");
+        assertEquals(10, ((Page<Case>) cases).getTotalElements());
     }
 
     @Test
@@ -1146,13 +1158,12 @@ public void testSimpleElasticCaseQuery() {
         checkNumberComparisonElastic("case", "places.p1.marking", "places.p1.marking");
 
         // task state comparison
-//        TODO: fix
-//        actual = evaluateQuery("case: tasks.t1.state eq enabled").getFullElasticQuery();
-//        expected = String.format("tasks.t1.state:%s", State.ENABLED);
-//        assertEquals(expected, actual);
-//        actual = evaluateQuery("case: tasks.t1.state eq disabled").getFullElasticQuery();
-//        expected = String.format("tasks.t1.state:%s", State.DISABLED);
-//        assertEquals(expected, actual);
+        actual = evaluateQuery("case: tasks.t1.state eq enabled").getFullElasticQuery();
+        expected = "taskIds:t1";
+        assertEquals(expected, actual);
+        actual = evaluateQuery("case: tasks.t1.state eq disabled").getFullElasticQuery();
+        expected = "NOT taskIds:t1";
+        assertEquals(expected, actual);
 
         // task userId comparison
         actual = evaluateQuery("case: tasks.t1.userId eq 'test'").getFullElasticQuery();