diff --git a/modules/mol/alg/pymod/dockq.py b/modules/mol/alg/pymod/dockq.py
index e8ec3f7a5e42d2bfdffa5929266ab9550aabbe14..7be3ca5d2a235bc58f5f15a7172a32f3a1da1e88 100644
--- a/modules/mol/alg/pymod/dockq.py
+++ b/modules/mol/alg/pymod/dockq.py
@@ -215,7 +215,7 @@ def _RMSDScores(mdl, ref, mdl_ch1, mdl_ch2, ref_ch1, ref_ch2, dist_thresh=10.0,
     # receptor is by definition the larger chain in ref
     n_ch1 = len(ref.FindChain(ref_ch1).residues)
     n_ch2 = len(ref.FindChain(ref_ch2).residues)
-    if n_ch1 > n_ch2:
+    if n_ch1 >= n_ch2:
         ref_receptor_residues = ref_ch1_residues.values()
         ref_ligand_residues = ref_ch2_residues.values()
         mdl_receptor_residues = \