diff --git a/wavinfo/wave_smpl_reader.py b/wavinfo/wave_smpl_reader.py
index 39b2b94..b520c54 100644
--- a/wavinfo/wave_smpl_reader.py
+++ b/wavinfo/wave_smpl_reader.py
@@ -93,9 +93,12 @@ class WavSmplReader:
                 repetition_count=unpacked_loop[5]))
 
         #: Sampler-specific user data.
-        self.sampler_udata: bytes = smpl_data[
-            header_size + loop_size * loop_count:
-            header_size + loop_size * loop_count + sampler_udata_length]
+        self.sampler_udata: bytes | None = None 
+
+        if sampler_udata_length > 0:
+            self.sampler_udata = smpl_data[
+                header_size + loop_size * loop_count:
+                header_size + loop_size * loop_count + sampler_udata_length]
 
     def to_dict(self):
         return {