diff --git a/pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java b/pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java
index 9b25d16402..91c4564e96 100644
--- a/pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java
+++ b/pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java
@@ -21,6 +21,7 @@ import java.util.Set;
 
 import net.sourceforge.pmd.AbstractConfiguration;
 import net.sourceforge.pmd.util.FileFinder;
+import net.sourceforge.pmd.util.FileUtil;
 
 import com.beust.jcommander.IStringConverter;
 import com.beust.jcommander.Parameter;
@@ -285,10 +286,10 @@ public class CPDConfiguration extends AbstractConfiguration {
                 if (excludedFile.isDirectory()) {
                     List<File> files = finder.findFilesFrom(excludedFile, languageFilter, true);
                     for (File f : files) {
-                        exclusions.add(f.getAbsolutePath());
+                        exclusions.add(FileUtil.normalizeFilename(f.getAbsolutePath()));
                     }
                 } else {
-                    exclusions.add(excludedFile.getAbsolutePath());
+                    exclusions.add(FileUtil.normalizeFilename(excludedFile.getAbsolutePath()));
                 }
             }
         }
@@ -296,7 +297,7 @@ public class CPDConfiguration extends AbstractConfiguration {
         FilenameFilter filter = new FilenameFilter() {
             public boolean accept(File dir, String name) {
                 File f = new File(dir, name);
-                if (exclusions.contains(f.getAbsolutePath())) {
+                if (exclusions.contains(FileUtil.normalizeFilename(f.getAbsolutePath()))) {
                     System.err.println("Excluding " + f.getAbsolutePath());
                     return false;
                 }
diff --git a/pmd-core/src/main/java/net/sourceforge/pmd/util/FileUtil.java b/pmd-core/src/main/java/net/sourceforge/pmd/util/FileUtil.java
index 0c8093f925..c5bfd3023a 100644
--- a/pmd-core/src/main/java/net/sourceforge/pmd/util/FileUtil.java
+++ b/pmd-core/src/main/java/net/sourceforge/pmd/util/FileUtil.java
@@ -10,6 +10,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
+import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
@@ -46,6 +47,20 @@ public final class FileUtil {
         return name;
     }
 
+    /**
+     * Normalizes the filename by taking the casing into account, e.g. on Windows,
+     * the filename is changed to lowercase only.
+     * @param fileName the file name
+     * @return the normalized file name
+     */
+    public static String normalizeFilename(String fileName) {
+        if (fileName != null && File.separatorChar == '\\') {
+            // windows
+            return fileName.toLowerCase(Locale.ROOT);
+        }
+        return fileName;
+    }
+
     /**
      * Collects a list of DataSources using a comma separated list of input file
      * locations to process.  If a file location is a directory, the directory
diff --git a/src/site/markdown/overview/changelog.md b/src/site/markdown/overview/changelog.md
index 7900b944a9..945bbd1d36 100644
--- a/src/site/markdown/overview/changelog.md
+++ b/src/site/markdown/overview/changelog.md
@@ -70,5 +70,6 @@
 **Bugfixes:**
 
 *   [#1370](https://sourceforge.net/p/pmd/bugs/1370/): ConsecutiveAppendsShouldReuse not detected properly on StringBuffer
+*   [#1402](https://sourceforge.net/p/pmd/bugs/1402/): Windows-Only: File exclusions are not case insensitive
 
 **API Changes:**