diff --git a/pyproject.toml b/pyproject.toml
index 4c8d56f1..b28c73f3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ description = "The WFDB Python package: tools for reading, writing, and processi
 authors = [{name = "The Laboratory for Computational Physiology", email = "contact@physionet.org"}]
 license = {text = "MIT License"}
 readme = "README.md"
-requires-python = ">= 3.10"
+requires-python = ">= 3.9"
 dependencies = [
     "numpy >= 1.26.4",
     "scipy >= 1.14.1",