Index: src/test/org/apache/lucene/search/TestBooleanMinShouldMatch.java
===================================================================
--- src/test/org/apache/lucene/search/TestBooleanMinShouldMatch.java	(revision 611183)
+++ src/test/org/apache/lucene/search/TestBooleanMinShouldMatch.java	(working copy)
@@ -284,7 +284,17 @@
         verifyNrHits(q, 0);
     }
 
+    public void testNoOptionalButMin2() throws Exception {
 
+        /* one required, no optional */
+        BooleanQuery q = new BooleanQuery();
+        q.add(new TermQuery(new Term("all", "all" )), BooleanClause.Occur.MUST);//true,  false);
+
+        q.setMinimumNumberShouldMatch(1); // 1 of 0 optional 
+
+        verifyNrHits(q, 0);
+    }
+
     public void testRandomQueries() throws Exception {
       final Random rnd = new Random(0);
 
Index: src/java/org/apache/lucene/search/BooleanQuery.java
===================================================================
--- src/java/org/apache/lucene/search/BooleanQuery.java	(revision 611183)
+++ src/java/org/apache/lucene/search/BooleanQuery.java	(working copy)
@@ -363,7 +363,7 @@
   }
 
   public Query rewrite(IndexReader reader) throws IOException {
-    if (clauses.size() == 1) {                    // optimize 1-clause queries
+    if (minNrShouldMatch == 0 && clauses.size() == 1) {                    // optimize 1-clause queries
       BooleanClause c = (BooleanClause)clauses.get(0);
       if (!c.isProhibited()) {			  // just return clause