Roy McMillan, one of baseball's smoothest-fielding shortstops of the 1950's with the Cincinnati Reds and later a New York Mets manager, died yesterday at Northeast Medical Center in Bonham, Tex. He was 68.

McMillan collapsed at his home in Bonham earlier in the day, having apparently suffered a heart attack, according to a friend, Bill Turnage.

In an era of superb National League shortstops, including the Chicago Cubs' Ernie Banks, the Brooklyn Dodgers' Pee Wee Reese and the New York Giants' Alvin Dark, McMillan was sometimes overshadowed. But he won Gold Gloves as the top fielder at his position from 1957 to 1959 and was an N.L. All-Star in 1956 and 1957.

A native of Bonham -- his father, the town barber, had the longtime Speaker of the House Sam Rayburn as a customer -- McMillan signed with the Reds' organization in 1947 out of Texas A & M. He had mostly been a softball player before being spotted at a Texas tryout camp, but four years later he was playing for Cincinnati at Crosley Field.

McMillan remained with the Reds through 1960, then spent three seasons with the Milwaukee Braves and then three years with the Mets. He was a mediocre hitter, with a .243 lifetime average for 16 seasons, but his fielding was eye-popping.

After watching McMillan take a base hit away from the Cardinals' Wally Moon one day and turn it into a double play, Eddie Stanky, the St. Louis manager, remarked, ''Hitting a ball toward Roy is like hitting it down a sewer.''

Jimmy Dykes, a star infielder of the 1920's and 30's and briefly McMillan's manager with the Reds, called him ''as fine a shortstop as I've ever seen -- any time, anywhere.''

Despite a string of injuries, including a ruptured spinal disk, McMillan played in 2,093 games. At the time he retired, only four other shortstops -- Bill Dahlen, Luke Appling, Rabbit Maranville and Reese -- had exceeded the 2,000-game total.

McMillan later coached for the Mets, then was named manager when Yogi Berra was fired on Aug. 6, 1975. He had a 26-27 record as manager as the team tied for third place in the N.L. East.

He was a scout for the Montreal Expos at the time of his death.

He is survived by his wife, Jody; a son, Marty, and a daughter, Patsy Richardson, both of Bonham; two brothers, Robert, of Euless, Tex., and Newman, of Albany, Ga.; a sister, Geraldine Trostel of Arlington, Tex., and three grandchildren.

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