diff --git a/src/core/peptidextp.cpp b/src/core/peptidextp.cpp
index 9da57dddb305068b564fe1805dc7f692171a94d6..1c2abad5b06e07f92f2b61b739f57fd7ed7c23b8 100644
--- a/src/core/peptidextp.cpp
+++ b/src/core/peptidextp.cpp
@@ -52,6 +52,7 @@ const QString PeptideXtp::getModifString() const {
                 aamodif << QString::number(aa_modif->getMass(), 'f', 2);
             }
         }
+        aamodif.sort();
         QString mod_str(aamodif.join("|"));
         if (!mod_str.isEmpty()) {
             modif_list << QString("%1%2:%3").arg(i).arg(amino_acid.getLetter()).arg(mod_str);
@@ -108,4 +109,4 @@ void PeptideXtp::applyLabelingMethod(LabelingMethodSp labeling_method_sp) {
 }
 const Label * PeptideXtp::getLabel() const {
   return _p_label;
-}
\ No newline at end of file
+}