diff --git a/training/unicharset_extractor.cpp b/training/unicharset_extractor.cpp
index 8042c4ab76860519dc369d176b4766e6df749440..7f7cc7b5031d69195b149515f1f5e34e289c85fa 100644
--- a/training/unicharset_extractor.cpp
+++ b/training/unicharset_extractor.cpp
@@ -72,7 +72,7 @@ void set_properties(UNICHARSET *unicharset, const char* const c_string) {
       unicharset->set_isalpha(id, 1);
       if (iswlower(wc))
         unicharset->set_islower(id, 1);
-      if (iswlower(wc))
+      if (iswupper(wc))
         unicharset->set_isupper(id, 1);
     }
     if (iswdigit(wc))