diff --git a/toyplot/coordinates.py b/toyplot/coordinates.py
index 901617e3..e722ec31 100644
--- a/toyplot/coordinates.py
+++ b/toyplot/coordinates.py
@@ -591,7 +591,7 @@ def _finalize(
             self._label_offset = self.label.offset if self.label.offset is not None else 22
             self._interactive_coordinates_location = self.interactive.coordinates.location if self.interactive.coordinates.location is not None else _opposite_location(self._tick_labels_location)
 
-            endpoints = numpy.row_stack(((x1, y1), (x2, y2)))
+            endpoints = numpy.vstack(((x1, y1), (x2, y2)))
             length = numpy.linalg.norm(endpoints[1] - endpoints[0])
             self.projection = _create_projection(
                 scale=self.scale,
diff --git a/toyplot/html.py b/toyplot/html.py
index da29aabf..8da69062 100644
--- a/toyplot/html.py
+++ b/toyplot/html.py
@@ -760,7 +760,7 @@ def _draw_marker(
 
 
 def _axis_transform(x1, y1, x2, y2, offset, return_length=False):
-    p = numpy.row_stack(((x1, y1), (x2, y2)))
+    p = numpy.vstack(((x1, y1), (x2, y2)))
     basis = p[1] - p[0]
     length = numpy.linalg.norm(basis)
     theta = numpy.rad2deg(numpy.arctan2(basis[1], basis[0]))