LEXINGTON, Ky. (AP) _ Lexington postal workers will give their stamp of approval when the city hosts the college basketball championships, canceling mail with the imprint of the NCAA tournament logo.

Pieces of mail dropped at a special Final Four station will be canceled with a horse running inside a fence, encircled by an outline of Kentucky. A basketball and ''1985 NCAA Championship'' will be beneath the logo.

''As far as we know, this is the first one done at an NCAA tournament,'' said Tom Adkins, Express mail coordinator in Lexington. ''We did it to kind of get wrapped up in the NCAA community-wise and give the people coming to Lexington something extra.''

The postal service began notifying stamp collectors a few weeks ago of the special cancellation and requests have arrived from Kansas, Nebraska, Arizona and Seattle, he said.

Those who come to Lexington need only mail their letters from the Civic Center Lobby between March 28-April 1. After the championship game that night, the cancellation will be destroyed.

Others can send stamped, self-addressed envelopes inside a larger envelope to: Postmaster, Final Four Station, Lexington, Ky., 40501-9998.

''It's not going to be a big money-maker. We just wanted to give the service and have a good time,'' Adkins said.