diff --git a/bindings/csharp/IOBuffer.cs b/bindings/csharp/IOBuffer.cs
index 1697f6ef4..a64d00a8c 100644
--- a/bindings/csharp/IOBuffer.cs
+++ b/bindings/csharp/IOBuffer.cs
@@ -134,10 +134,10 @@ private void Dispose(bool clean)
         /// <remarks>The number of samples written will not exceed the size of the buffer.</remarks>
         public void fill(byte[] array)
         {
-            int length = (int) iio_buffer_end(buf) - (int) iio_buffer_start(buf);
+            long length = (long) iio_buffer_end(buf) - (long) iio_buffer_start(buf);
             if (length > array.Length)
                 length = array.Length;
-            Marshal.Copy(array, 0, iio_buffer_start(buf), length);
+            Marshal.Copy(array, 0, iio_buffer_start(buf), (int)length);
         }
     }
 }