diff --git a/blobstore/src/main/java/org/jclouds/blobstore/domain/internal/BlobBuilderImpl.java b/blobstore/src/main/java/org/jclouds/blobstore/domain/internal/BlobBuilderImpl.java
index 2f0cf19183..2069220abf 100644
--- a/blobstore/src/main/java/org/jclouds/blobstore/domain/internal/BlobBuilderImpl.java
+++ b/blobstore/src/main/java/org/jclouds/blobstore/domain/internal/BlobBuilderImpl.java
@@ -178,6 +178,7 @@ public class BlobBuilderImpl implements BlobBuilder {
 
       @Override
       public PayloadBlobBuilder contentLength(long contentLength) {
+         checkArgument(contentLength >= 0, "content length must be non-negative");
          payload.getContentMetadata().setContentLength(contentLength);
          return this;
       }