diff --git a/src/Scrutor/TypeSourceSelector.cs b/src/Scrutor/TypeSourceSelector.cs
index e3f836b..f0a53d0 100644
--- a/src/Scrutor/TypeSourceSelector.cs
+++ b/src/Scrutor/TypeSourceSelector.cs
@@ -154,7 +154,7 @@ private IImplementationTypeSelector InternalFromAssembliesOf(IEnumerable<Type> t
 
     private IImplementationTypeSelector InternalFromAssemblies(IEnumerable<Assembly> assemblies)
     {
-        return AddSelector(assemblies.SelectMany(asm => asm.DefinedTypes).Select(x => x.AsType()));
+        return AddSelector(assemblies.SelectMany(asm => asm.ExportedTypes);
     }
 
     private static IEnumerable<Assembly> LoadAssemblies(IEnumerable<AssemblyName> assemblyNames)