diff --git a/ApplicationCode/ProjectDataModel/RimRegularLegendConfig.cpp b/ApplicationCode/ProjectDataModel/RimRegularLegendConfig.cpp
index ff385d3a8c..22e680a2bb 100644
--- a/ApplicationCode/ProjectDataModel/RimRegularLegendConfig.cpp
+++ b/ApplicationCode/ProjectDataModel/RimRegularLegendConfig.cpp
@@ -686,7 +686,7 @@ QString RimRegularLegendConfig::categoryNameFromCategoryValue(double categoryRes
 //--------------------------------------------------------------------------------------------------
 double RimRegularLegendConfig::categoryValueFromCategoryName(const QString& categoryName) const
 {
-    for (int i = 0; i < m_categoryNames.size(); i++)
+    for (int i = 0; i < (int)m_categoryNames.size(); i++)
     {
         if (cvfqt::Utils::toQString(m_categoryNames[i]).compare(categoryName, Qt::CaseInsensitive) == 0)
         {