diff --git a/ecoval/matchall.py b/ecoval/matchall.py
index fd19960..fab5b33 100644
--- a/ecoval/matchall.py
+++ b/ecoval/matchall.py
@@ -652,6 +652,10 @@ def matchup(
     point_surface_req = copy.deepcopy(point_surface)
     benthic_req = copy.deepcopy(benthic)
 
+    # throw an error if all of these are empty
+    if len(surface) == 0 and len(bottom) == 0 and len(benthic) == 0:
+        raise ValueError("Please provide at least one variable to matchup")
+
     if isinstance(exclude, str):
         exclude = [exclude]