diff --git a/stardao-dynamodb/src/main/java/io/stardog/stardao/dynamodb/mapper/JacksonItemMapper.java b/stardao-dynamodb/src/main/java/io/stardog/stardao/dynamodb/mapper/JacksonItemMapper.java
index 79a113d..80dca0c 100644
--- a/stardao-dynamodb/src/main/java/io/stardog/stardao/dynamodb/mapper/JacksonItemMapper.java
+++ b/stardao-dynamodb/src/main/java/io/stardog/stardao/dynamodb/mapper/JacksonItemMapper.java
@@ -104,7 +104,9 @@ protected Item renameItem(Item item, Map<String,String> renames) {
         Item renamedItem = new Item();
         for (String key : map.keySet()) {
             String renamedKey = renames.getOrDefault(key, key);
-            renamedItem.with(renamedKey, item.get(key));
+            if (renamedKey != null && !"".equals(renamedKey)) {
+                renamedItem.with(renamedKey, item.get(key));
+            }
         }
         return renamedItem;
     }
diff --git a/stardao-mongodb/src/main/java/io/stardog/stardao/mongodb/mapper/jackson/JacksonDocumentMapper.java b/stardao-mongodb/src/main/java/io/stardog/stardao/mongodb/mapper/jackson/JacksonDocumentMapper.java
index 08d32ac..3de7317 100644
--- a/stardao-mongodb/src/main/java/io/stardog/stardao/mongodb/mapper/jackson/JacksonDocumentMapper.java
+++ b/stardao-mongodb/src/main/java/io/stardog/stardao/mongodb/mapper/jackson/JacksonDocumentMapper.java
@@ -109,7 +109,9 @@ protected Document renameDocument(Document doc, Map<String,String> renames) {
         Document renamedDoc = new Document();
         for (String key : doc.keySet()) {
             String renamedKey = renames.getOrDefault(key, key);
-            renamedDoc.put(renamedKey, doc.get(key));
+            if (renamedKey != null && !"".equals(renamedKey)) {
+                renamedDoc.put(renamedKey, doc.get(key));
+            }
         }
         return renamedDoc;
     }