diff --git a/src/vatom/COM.cpp b/src/vatom/COM.cpp
index 9e9ac4890c41a0b3ca94619586f085f5a394a8a7..da0259c9095b255400da1f2e9cf3779c72120086 100644
--- a/src/vatom/COM.cpp
+++ b/src/vatom/COM.cpp
@@ -98,7 +98,7 @@ COM::COM(const ActionOptions&ao):
     log.printf(" %d",atoms[i].serial());
   }
   log.printf("\n");
-  if(!nopbc) {
+  if(nopbc) {
     log<<"  PBC will be ignored\n";
   } else {
     log<<"  broken molecules will be rebuilt assuming atoms are in the proper order\n";
diff --git a/src/vatom/Center.cpp b/src/vatom/Center.cpp
index 70269b52c732ca346c5914a73314dc92c73d3f88..29d59349430e9cffeb6725b96de15f85e5321c89 100644
--- a/src/vatom/Center.cpp
+++ b/src/vatom/Center.cpp
@@ -131,7 +131,7 @@ Center::Center(const ActionOptions&ao):
       log.printf("\n");
     }
   }
-  if(!nopbc) {
+  if(nopbc) {
     log<<"  PBC will be ignored\n";
   } else {
     log<<"  broken molecules will be rebuilt assuming atoms are in the proper order\n";