diff --git a/src/java/org/apache/solr/update/DocumentBuilder.java b/src/java/org/apache/solr/update/DocumentBuilder.java
index 14dc78d2501..f9d94d8538a 100644
--- a/src/java/org/apache/solr/update/DocumentBuilder.java
+++ b/src/java/org/apache/solr/update/DocumentBuilder.java
@@ -188,8 +188,13 @@ public class DocumentBuilder {
       SchemaField[] destArr = schema.getCopyFields(name);
       
       // load each field value
+      boolean hasField = false;
       for( Object v : field ) {
+        if( v == null ) {
+          continue;
+        }
         String val = null;
+        hasField = true;
         
         // TODO!!! HACK -- date conversion
         if( sfield != null && v instanceof Date && sfield.getType() instanceof DateField ) {
@@ -232,7 +237,7 @@ public class DocumentBuilder {
       }
       
       // make sure the field was used somehow...
-      if( !used ) {
+      if( !used && hasField ) {
         throw new SolrException( SolrException.ErrorCode.BAD_REQUEST,"ERROR:unknown field '" + name + "'");
       }
     }
diff --git a/src/test/org/apache/solr/update/DocumentBuilderTest.java b/src/test/org/apache/solr/update/DocumentBuilderTest.java
index 4152cb34cf9..04dabf060a1 100644
--- a/src/test/org/apache/solr/update/DocumentBuilderTest.java
+++ b/src/test/org/apache/solr/update/DocumentBuilderTest.java
@@ -17,6 +17,7 @@
 
 package org.apache.solr.update;
 
+import org.apache.lucene.document.Document;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.SolrInputDocument;
 import org.apache.solr.core.SolrCore;
@@ -47,4 +48,15 @@ public class DocumentBuilderTest extends AbstractSolrTestCase {
       assertEquals( "should be bad request", 400, ex.code() );
     }
   }
+
+  public void testNullField() 
+  {
+    SolrCore core = SolrCore.getSolrCore();
+    
+    // make sure a null value is not indexed
+    SolrInputDocument doc = new SolrInputDocument();
+    doc.addField( "name", null, 1.0f );
+    Document out = DocumentBuilder.toDocument( doc, core.getSchema() );
+    assertNull( out.get( "name" ) );
+  }
 }