diff --git a/bokeh/plotting.py b/bokeh/plotting.py
index <HASH>..<HASH> 100644
--- a/bokeh/plotting.py
+++ b/bokeh/plotting.py
@@ -766,6 +766,11 @@ def scatter(*args, **kwargs):
     markertype = kwargs.get("type", "circle")
     x_name = names[0]
 
+    # TODO this won't be necessary when markers are made uniform
+    if markertype == "circle":
+        if "radius" not in kwargs:
+            kwargs["radius"] = kwargs.get("size")/2
+
     # TODO: How to handle this? Just call curplot()?
     if not len(color_fields.intersection(set(kwargs.keys()))):
         kwargs['color'] = get_default_color()
adapt size argmuent to circle scatter