diff --git a/pdbfixer/pdbfixer.py b/pdbfixer/pdbfixer.py
index 431b021..35aa11b 100644
--- a/pdbfixer/pdbfixer.py
+++ b/pdbfixer/pdbfixer.py
@@ -1263,6 +1263,10 @@ def main():
         if options.residues:
             if options.verbose: print('Finding missing residues...')
             fixer.findMissingResidues()
+            for residueNames in fixer.missingResidues.values():
+                for residueName in residueNames:
+                    if residueName not in fixer.templates:
+                        raise(KeyError("Cannot find residue %s in template library!" % residueName))
         else:
             fixer.missingResidues = {}
         if options.nonstandard: