diff --git a/icu4j/main/classes/core/src/com/ibm/icu/text/CharsetRecog_UTF8.java b/icu4j/main/classes/core/src/com/ibm/icu/text/CharsetRecog_UTF8.java
index 735b667cc8..454e81c97c 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/text/CharsetRecog_UTF8.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/text/CharsetRecog_UTF8.java
@@ -1,6 +1,6 @@
 /**
 *******************************************************************************
-* Copyright (C) 2005 - 2012, International Business Machines Corporation and  *
+* Copyright (C) 2005 - 2013, International Business Machines Corporation and  *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
@@ -85,8 +85,10 @@ class CharsetRecog_UTF8 extends CharsetRecognizer {
         } else if (numValid > 0 && numInvalid == 0) {
             confidence = 80;
         } else if (numValid == 0 && numInvalid == 0) {
-            // Plain ASCII.  
-            confidence = 10;            
+            // Plain ASCII. Confidence must be > 10, it's more likely than UTF-16, which
+            //              accepts ASCII with confidence = 10.
+            // TODO: add plain ASCII as an explicitly detected type.
+            confidence = 15;            
         } else if (numValid > numInvalid*10) {
             // Probably corruput utf-8 data.  Valid sequences aren't likely by chance.
             confidence = 25;
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/charsetdet/CharsetDetectionTests.xml b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/charsetdet/CharsetDetectionTests.xml
index 671e885b50..1fd633dc7a 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/charsetdet/CharsetDetectionTests.xml
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/charsetdet/CharsetDetectionTests.xml
@@ -553,4 +553,9 @@ Conference Program
     <test-case id="bug-10532-utf-16" encodings="UTF-8 UTF-16BE UTF-16LE UTF-32BE UTF-32LE">
     foo 東京・銀座の歌舞伎座。４月に新調された４枚の緞帳のうち３枚は、京都の川島織物セルコンが織った朝日新聞デジタル会員（有料・無料）にご登録いただくと、様々な特典・サービスが受けられます。
     </test-case>
+    
+    <test-case id="bug-10532-ASCII" encodings="UTF-8 UTF-16BE UTF-16LE UTF-32BE UTF-32LE">
+    <!--  Note that plain 7 bit ASCII is detected as UTF-8 -->
+    ,1,,,5
+    </test-case>
 </charset-detection-tests>