Melvin Gregorio Rosario (born May 25, 1973) is a Dominican former Major League Baseball player. Rosario played for the Baltimore Orioles in the 1997 season. In four games, he had no hits in 3 at-bats, with one error at catcher. Rosario was a switch hitter and threw right-handed.
He was signed by the San Diego Padres as an amateur free agent in 1991. He last played professionally in for the Atlantic City Surf of the Atlantic League.