diff --git a/pyproject.toml b/pyproject.toml
index 212a419..8f0341a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,5 +24,5 @@ classifiers = [
 Homepage = "https://github.com/bonfus/muLFC"
 
 [build-system]
-requires = ["setuptools>=61"]
+requires = ["setuptools>=61", "numpy>=1.8"]
 build-backend = "setuptools.build_meta"