Thieves made off from a Doncaster building site with road roller.
Police were called to the site on Woodfield Way, Balby, after the raid at around 6pm on Monday evening.
They are studying closed circuit television pictures at the site.
They are keen to hear from anyone who may have seen a road roller being driven around that time. It was a yellow and black Bomag roller.
Witnesses to either crime can call police by telephoning 101.