diff --git a/WHATSNEW b/WHATSNEW
index 87927e2b9..222f80fbb 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -10,6 +10,8 @@ Changes that could break older environments:
 Fixed bugs:
 -----------
 
+* <checksum> with file and todir option failed. Bugzilla report 37386.
+
 Other changes:
 --------------
 
diff --git a/src/main/org/apache/tools/ant/taskdefs/Checksum.java b/src/main/org/apache/tools/ant/taskdefs/Checksum.java
index e20b2aa64..6a6364ea6 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Checksum.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Checksum.java
@@ -398,6 +398,10 @@ public class Checksum extends MatchingTask implements Condition {
                 }
             }
             if (file != null) {
+                if (totalproperty != null || todir != null) {
+                    relativeFilePaths.put(
+                        file, file.getName().replace(File.separatorChar, '/'));
+                }
                 addToIncludeFileMap(file);
             }
             return generateChecksums();