diff --git a/python/src/com/jetbrains/python/psi/types/PyTypeInferenceFromUsedAttributesUtil.java b/python/src/com/jetbrains/python/psi/types/PyTypeInferenceFromUsedAttributesUtil.java
index 7fdb20346154..3e55067fa35a 100644
--- a/python/src/com/jetbrains/python/psi/types/PyTypeInferenceFromUsedAttributesUtil.java
+++ b/python/src/com/jetbrains/python/psi/types/PyTypeInferenceFromUsedAttributesUtil.java
@@ -6,11 +6,11 @@ import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.roots.ProjectRootManager;
-import com.intellij.openapi.util.Comparing;
+import com.intellij.openapi.util.*;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.PsiNamedElement;
 import com.intellij.psi.PsiReference;
-import com.intellij.psi.util.QualifiedName;
+import com.intellij.psi.util.*;
 import com.intellij.util.Function;
 import com.intellij.util.containers.ContainerUtil;
 import com.jetbrains.python.PyNames;
@@ -47,6 +47,8 @@ public class PyTypeInferenceFromUsedAttributesUtil {
   );
 
   private static final Logger LOG = Logger.getInstance(PyTypeInferenceFromUsedAttributesUtil.class);
+  private static final CachedAncestorsFastProvider ourCachedAncestorsProvider = new CachedAncestorsFastProvider();
+  private static final RecursionGuard ourRecursionGuard = RecursionManager.createGuard("py.types.from.attrs.rec.guard");
 
   private PyTypeInferenceFromUsedAttributesUtil() {
     // empty
@@ -103,13 +105,13 @@ public class PyTypeInferenceFromUsedAttributesUtil {
       if (PyUserSkeletonsUtil.isUnderUserSkeletonsDirectory(candidate.getContainingFile())) {
         continue;
       }
-      if (getAllInheritedAttributeNames(candidate, context).containsAll(seenAttrs)) {
+      if (getAllInheritedAttributeNames(candidate).containsAll(seenAttrs)) {
         suitableClasses.add(candidate);
       }
     }
 
     for (PyClass candidate : Lists.newArrayList(suitableClasses)) {
-      for (PyClass ancestor : candidate.getAncestorClasses()) {
+      for (PyClass ancestor : getAncestorClassesFast(candidate)) {
         if (suitableClasses.contains(ancestor)) {
           suitableClasses.remove(candidate);
         }
@@ -126,9 +128,9 @@ public class PyTypeInferenceFromUsedAttributesUtil {
   }
 
   @NotNull
-  private static Set<String> getAllInheritedAttributeNames(@NotNull PyClass candidate, @NotNull TypeEvalContext context) {
+  private static Set<String> getAllInheritedAttributeNames(@NotNull PyClass candidate) {
     final Set<String> availableAttrs = Sets.newHashSet(getAllDeclaredAttributeNames(candidate));
-    for (PyClass parent : candidate.getAncestorClasses(context)) {
+    for (PyClass parent : getAncestorClassesFast(candidate)) {
       availableAttrs.addAll(getAllDeclaredAttributeNames(parent));
     }
     return availableAttrs;
@@ -278,6 +280,37 @@ public class PyTypeInferenceFromUsedAttributesUtil {
     }
   }
 
+  @NotNull
+  private static Set<PyClass> getAncestorClassesFast(@NotNull PyClass pyClass) {
+    final CachedValuesManager manager = CachedValuesManager.getManager(pyClass.getProject());
+    return manager.getParameterizedCachedValue(pyClass, CachedAncestorsFastProvider.KEY, ourCachedAncestorsProvider, false, pyClass);
+  }
+
+  private static class CachedAncestorsFastProvider implements ParameterizedCachedValueProvider<Set<PyClass>, PyClass> {
+    static Key<ParameterizedCachedValue<Set<PyClass>, PyClass>> KEY = Key.create("py.types.from.attrs.cached.ancestors.fast");
+
+    @NotNull
+    @Override
+    public CachedValueProvider.Result<Set<PyClass>> compute(@NotNull PyClass pyClass) {
+      final HashSet<PyClass> result = Sets.newHashSet();
+      for (final PyClass baseClass : pyClass.getSuperClasses()) {
+        final Computable<Set<PyClass>> computable = new Computable<Set<PyClass>>() {
+          @Override
+          public Set<PyClass> compute() {
+            return getAncestorClassesFast(baseClass);
+          }
+        };
+        final Set<PyClass> baseClassAncestors = ourRecursionGuard.doPreventingRecursion(baseClass, false, computable);
+        result.add(baseClass);
+        if (baseClassAncestors != null) {
+          result.addAll(baseClassAncestors);
+        }
+      }
+      return CachedValueProvider.Result.create(Collections.unmodifiableSet(result),
+                                               PsiModificationTracker.OUT_OF_CODE_BLOCK_MODIFICATION_COUNT);
+    }
+  }
+
   enum Priority {
     BUILTIN,
     SAME_FILE,
diff --git a/python/testData/typesFromAttributes/cyclicInheritance/main.py b/python/testData/typesFromAttributes/cyclicInheritance/main.py
new file mode 100644
index 000000000000..530c522ca408
--- /dev/null
+++ b/python/testData/typesFromAttributes/cyclicInheritance/main.py
@@ -0,0 +1,9 @@
+from module import A
+
+class B(A):
+    def unique(self):
+        pass
+
+x = undefined()
+x.unique()
+x
\ No newline at end of file
diff --git a/python/testData/typesFromAttributes/cyclicInheritance/module.py b/python/testData/typesFromAttributes/cyclicInheritance/module.py
new file mode 100644
index 000000000000..82cd4f4fcfa8
--- /dev/null
+++ b/python/testData/typesFromAttributes/cyclicInheritance/module.py
@@ -0,0 +1,4 @@
+from main import B
+
+class A(B):
+    pass
diff --git a/python/testSrc/com/jetbrains/python/PyTypeFromUsedAttributesTest.java b/python/testSrc/com/jetbrains/python/PyTypeFromUsedAttributesTest.java
index d9498e1419ac..39bf35b666be 100644
--- a/python/testSrc/com/jetbrains/python/PyTypeFromUsedAttributesTest.java
+++ b/python/testSrc/com/jetbrains/python/PyTypeFromUsedAttributesTest.java
@@ -190,6 +190,17 @@ public class PyTypeFromUsedAttributesTest extends PyTestCase {
                "list | MySortable | OtherClassA | OtherClassB | unknown");
   }
 
+  public void testCyclicInheritance() {
+    myFixture.copyDirectoryToProject(getTestName(true), "");
+    myFixture.configureByFile("main.py");
+    final PyReferenceExpression referenceExpression = findLastReferenceByText("x");
+    assertNotNull(referenceExpression);
+    final TypeEvalContext context = TypeEvalContext.userInitiated(referenceExpression.getContainingFile()).withTracing();
+    final PyType actual = context.getType(referenceExpression);
+    final String actualType = PythonDocumentationProvider.getTypeName(actual, context);
+    assertEquals("unknown", actualType);
+  }
+
   private void doTestType(@NotNull String text, @NotNull String expectedType) {
     myFixture.configureByText(PythonFileType.INSTANCE, text);
     final PyReferenceExpression referenceExpression = findLastReferenceByText("x");