diff --git a/net/FlatBuffers/FlatBufferBuilder.cs b/net/FlatBuffers/FlatBufferBuilder.cs
index e550f90f833..e08db847be8 100644
--- a/net/FlatBuffers/FlatBufferBuilder.cs
+++ b/net/FlatBuffers/FlatBufferBuilder.cs
@@ -438,7 +438,8 @@ public void AddOffset(int off)
             if (off > Offset)
                 throw new ArgumentException();
 
-            off = Offset - off + sizeof(int);
+            if (off != 0)
+                off = Offset - off + sizeof(int);
             PutInt(off);
         }
 
diff --git a/net/FlatBuffers/Table.cs b/net/FlatBuffers/Table.cs
index 21ef7dc8b82..2aaa86e99b3 100644
--- a/net/FlatBuffers/Table.cs
+++ b/net/FlatBuffers/Table.cs
@@ -65,7 +65,11 @@ public static int __indirect(int offset, ByteBuffer bb)
         // Create a .NET String from UTF-8 data stored inside the flatbuffer.
         public string __string(int offset)
         {
-            offset += bb.GetInt(offset);
+            int stringOffset = bb.GetInt(offset);
+            if (stringOffset == 0)
+                return null;
+
+            offset += stringOffset;
             var len = bb.GetInt(offset);
             var startPos = offset + sizeof(int);
             return bb.GetStringUTF8(startPos, len);