The tour announced Thursday the native of Australia should have been No. 1 after the 1976 season when she beat American Chris Evert 6-3, 5-7, 6-3 at the final of the 1976 Virginia Slims Championships in Los Angeles.
On its Web site, the tour stated the belated accolade follows recent search of the Sony Ericsson WTA Tour Rankings archives, which revealed a handful of paper records were missing between April and July 1976, most notably the ranking period April 26-May 9.
"I'm simply delighted," Cawley said from her home in Noosa, Queensland. "Most tournaments were on grass, which helped the serve and volley part of my game and for five or six months I felt virtually unbeatable."
To celebrate, the tour sent her a Waterford Crystal trophy.
Cawley played professionally from 1971-83 and won seven Grand Slam singes titles, including four Australian Opens.