diff --git a/cameo/strain_design/deterministic/flux_variability_based.py b/cameo/strain_design/deterministic/flux_variability_based.py
index 5be430248..55dcf04c7 100644
--- a/cameo/strain_design/deterministic/flux_variability_based.py
+++ b/cameo/strain_design/deterministic/flux_variability_based.py
@@ -576,7 +576,7 @@ def __len__(self):
 
     # TODO: Make an iterator that returns designs from the different enforced levels
     def __iter__(self):
-        pass
+        return iter(self.reactions)
 
     def __eq__(self, other):
         return isinstance(other, self.__class__) and \