diff --git a/Tests/test_file_pdf.py b/Tests/test_file_pdf.py
index 2b5c12ea3..bb003a32c 100644
--- a/Tests/test_file_pdf.py
+++ b/Tests/test_file_pdf.py
@@ -67,6 +67,7 @@ class TestFilePdf(PillowTestCase):
     def test_resolution(self):
         self.helper_save_as_pdf("RGB", resolution=300.5)
         self.helper_save_as_pdf("RGB", resolution=(300, 150))
+        self.assertRaises(ValueError, self.helper_save_as_pdf, "RGB", resolution=-100)
 
     def test_unsupported_mode(self):
         im = hopper("LA")
diff --git a/src/PIL/PdfImagePlugin.py b/src/PIL/PdfImagePlugin.py
index 9e01ea692..eea3d9e32 100644
--- a/src/PIL/PdfImagePlugin.py
+++ b/src/PIL/PdfImagePlugin.py
@@ -63,6 +63,8 @@ def _save(im, fp, filename, save_all=False):
     else:
         pdf_width_res = resolution[0]
         pdf_height_res = resolution[1]
+    if pdf_width_res <= 0 or pdf_height_res <= 0:
+        raise ValueError("Resolution must be > 0")
 
     info = {
         "title": None if is_appending else os.path.splitext(