diff --git a/pandas_plink/_write.py b/pandas_plink/_write.py
index 3d11a96..c86cf54 100755
--- a/pandas_plink/_write.py
+++ b/pandas_plink/_write.py
@@ -264,6 +264,7 @@ def _write_fam(filepath: Path, G: DataArray):
         sep="\t",
         header=False,
         encoding="ascii",
+        lineterminator="\n",
     )
 
 
@@ -290,4 +291,5 @@ def _write_bim(filepath: Path, G: DataArray):
         sep="\t",
         header=False,
         encoding="ascii",
+        lineterminator="\n",
     )