diff --git a/pokemongo_bot/cell_workers/evolve_pokemon.py b/pokemongo_bot/cell_workers/evolve_pokemon.py
index 431633aab8..7cd37f77bc 100644
--- a/pokemongo_bot/cell_workers/evolve_pokemon.py
+++ b/pokemongo_bot/cell_workers/evolve_pokemon.py
@@ -40,7 +40,7 @@ def work(self):
 
         if self.evolve_all[0] != 'all':
             # check for negation
-            negate = filter(lambda x: x[0] == '-', self.evolve_all)
+            negate = filter(lambda x: len(x) > 0 and x[0] == '-', self.evolve_all)
 
             # if there are things to negate
             if len(negate) > 0: