Clem Labine, the All-Star relief pitcher of the 1950s who helped bring the Brooklyn Dodgers four pennants and their only World Series championship, died yesterday in Vero Beach, Fla. He was 80.

The cause was a pair of strokes he sustained after being hospitalized with pneumonia, said Labine's wife, Barbara.

A right-hander with an outstanding sinker and curveball, familiar to fans at Ebbets Field for his distinctive crew cut, Labine was a late-inning presence on the teams whose members became known as the Boys of Summer.

He led the National League in saves in 1956 (with 19) and '57 (with 17) and he was an All-Star in both seasons. In 1955, he appeared in a National League-high 60 games, posting a 13-5 record with 11 saves, then beat the Yankees in relief in Game 4 of the World Series and saved Game 5. The Dodgers went on to win in seven games after having lost to the Yankees in the Series five times.

Pitching in the major leagues from 1950 to 1962, Labine started only 38 games in 513 appearances. But he made several memorable starts.

In the playoff for the 1951 pennant, he threw a six-hit complete game at the Polo Grounds in the Dodgers' 10-0 victory over the New York Giants in Game 2, a day before Bobby Thomson's pennant-winning home run off the Dodgers' Ralph Branca. In the 1956 World Series, Labine beat the Yankees, 1-0, on a seven-hitter in Game 6, pitching all 10 innings, a day after the Yankees' Don Larsen threw a perfect game.

''I always thought Clem would've had a great career as a starting pitcher,'' Labine's teammate Carl Erskine said yesterday in a statement. ''But he told me: 'I don't want to start. I liked the pressure of coming into the game with everything on the line.' ''

Clement Walter Labine was born Aug. 6, 1926, in Lincoln, R.I., and grew up in Woonsocket, the son of a weaver. He signed with the Dodgers in 1944 and began to flourish as a reliever in 1953, having mastered a sinker in the Venezuelan winter league.

Labine's sinker induced batters to pound balls into the dirt. ''They go to swing at it, and it drops on you, and you get the top of the ball,'' Labine told Peter Golenbock in ''Bums,'' an oral history of the Brooklyn Dodgers. ''So you're not going to hit a lot of line drives off of me, just a lot of ground balls.''

Labine remained with the Dodgers when they moved to Los Angeles in 1958 and pitched on their '59 World Series championship team. He was traded to the Detroit Tigers during the 1960 season, joined the Pittsburgh Pirates later that year and pitched in their World Series victory over the Yankees. He finished his career with the original Mets in 1962.

Pitching for 13 seasons, he had a career record of 77-56 with 96 saves.

After retiring from baseball, Labine, who lived in Cumberland, R.I., and Vero Beach, was an executive and designer for a men's sportswear company and a bank executive. In an interview with Roger Kahn for his book ''The Boys of Summer,'' Labine told of his family's travails after he left the game. His son, Clem Jr., known as Jay, enlisted in the Marines, then lost a leg when he stepped on a land mine in the Vietnam War.

In addition to his wife and his son, of Woonsocket, Labine is survived by his daughters Barbara Grubbs of Reno; Gail Ponanski and Kim Archambault of Smithfield, R.I.; the four children from his marriage to his first wife, also named Barbara, who died in 1976; his daughter Susan Gershkoff, of Lincoln, R.I, from his second marriage; five grandchildren; and a great-grandchild.

Through those summers of the 1950s, Labine was a confident figure, relieving pitching mainstays like Erskine, Don Newcombe, Preacher Roe and Johnny Podres.

''If you had a lead, there was this thing where about the seventh or eighth inning, where he'd get up, sort of a ritual, and walk down to the bullpen,'' the former Dodgerspitcher Roger Craig told Bob Cairns in ''Pen Men,'' an oral history of relief pitching. ''Clem was kind of a cocky, arrogant type, which was good. I liked it. He'd fold his glove up and put it in his pocket. I can see him now, strutting down to the bullpen and the fans cheering.''

Left to Right Clem Labine, Carl Furillo, Pee Wee Reese

Clement W Labine