Frank Cashen, the sportswriter turned baseball executive who built pennant-winning teams with the Baltimore Orioles and then transformed the Mets from perennial losers to the World Series champions of 1986, died on Monday at a hospital near his home in Easton, Md. He was 88.

The Mets announced his death on their website.

In nearly a quarter-century as a baseball administrator, Mr. Cashen made shrewd trades, but he focused on building farm systems, even with the arrival in the mid-1970s of bidding wars for high-priced free agents. It was something of an old-fashioned strategy that fit perfectly with Mr. Cashen’s collection of bow ties from a bygone era in men’s fashion.

He joined the Mets in 1980, after they had finished last in the National League East for three straight seasons, and built a 1986 championship ball club featuring Dwight Gooden, Darryl Strawberry, Mookie Wilson, Lenny Dykstra, Jesse Orosco, Wally Backman and Roger McDowell from the Mets’ farm system, together with Gary Carter, Keith Hernandez, Ron Darling, Sid Fernandez, Bobby Ojeda, Ray Knight and Howard Johnson, all obtained in trades.

Mr. Cashen hired Davey Johnson, his second baseman when he ran the Orioles, as the Mets’ manager before the 1984 season, and Johnson led a 1986 team that won 108 games in the regular season, capturing the National League East title by 21 ½ games. Drawing more than 2.7 million fans to Shea Stadium and eclipsing the Yankees in the New York baseball spotlight, the ’86 Mets, a cocky if not arrogant crew, went on to defeat the Red Sox in a seven-game World Series remembered chiefly for the disastrous error by Boston’s first baseman, Bill Buckner, in Game 6.