diff --git a/plugins/svn4idea/src/org/jetbrains/idea/svn/annotate/SvnAnnotationProvider.java b/plugins/svn4idea/src/org/jetbrains/idea/svn/annotate/SvnAnnotationProvider.java
index b4d18c4b111b..2e3934c149ab 100644
--- a/plugins/svn4idea/src/org/jetbrains/idea/svn/annotate/SvnAnnotationProvider.java
+++ b/plugins/svn4idea/src/org/jetbrains/idea/svn/annotate/SvnAnnotationProvider.java
@@ -204,6 +204,7 @@ public class SvnAnnotationProvider implements AnnotationProvider, VcsCacheableAn
     for (int i = 0; i < size; i++) {
       if (svnFileAnnotation.getAnnotationSourceSwitcher().mergeSourceAvailable(i)) {
         final VcsRevisionNumber number = svnFileAnnotation.getLineRevisionNumber(i);
+        if (number == null) continue;
         merged.put(i, number);
         addMap.put(number, svnFileAnnotation.getRevision(((SvnRevisionNumber) number).getRevision().getNumber()));
       }