A driver who left his van running while he went into a shop returned to find it stolen.
The silver Vahxhall Vivaro was taken from Main Street, Northiam, 12 miles north of Hastings, between 6.30pm and 6.40pm on Thursday July 10.
A Sussex Police spokesman said: "We would like to talk to anyone who saw what happened to the unattended van or has any information as to its whereabouts. It appears to be the actions of an opportunist thief and we would like to remind drivers to remember to secure your vehicles before you leave them, even if they plan to leave them unattended for a few moments."
Any witness or anyone with information is asked to call 101 or email email@example.com quoting serial 1252 of 10/07. Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.