May was the second-richest month for Kansas City's riverboat casinos, which won $48.7 million from gamblers.
According to a report in the Kansas City Star, the results approached March's $54.3 million, the best month ever for the region.
The casinos are on a pace to win $576 million, beating last year's record $535 million performance.
Leading the pace were Ameristar and Isle of Capri. Ameristar edged Harrah's North Kandas City by .01 percent. The Argosy Riverside accounted for 16 percent of the market's win. Isle, located near downtown Kansas City, also grabbed 16 percent of total revenues.