diff --git a/sahi/utils/coco.py b/sahi/utils/coco.py
index 1777555aa..e84f2f3d3 100644
--- a/sahi/utils/coco.py
+++ b/sahi/utils/coco.py
@@ -130,7 +130,7 @@ def from_coco_annotation_dict(cls, annotation_dict: Dict, category_name: Optiona
             annotation_dict: dict
                 COCO formatted annotation dict (with fields "bbox", "segmentation", "category_id")
         """
-        if annotation_dict.__contains__("segmentation") and not isinstance(annotation_dict["segmentation"], list):
+        if annotation_dict.__contains__("segmentation") and isinstance(annotation_dict["segmentation"], dict):
             has_rle_segmentation = True
             logger.warning(
                 f"Segmentation annotation for id {annotation_dict['id']} is skipped since RLE segmentation format is not supported."