Rick Schu, the team's hitting coach, also was fired after Thursday's 4-3, 10-inning loss to San Diego, while pitching coach Bryan Price resigned in anger.
"I believe that Bob is an outstanding major league manager," Price told MLB.com. "It tears my heart out that he's not managing this ball club anymore."
Hinch, a 34-year-old former major league catcher during a seven-year career, has helped guide the organization's young stars like infielders Stephen Drew and Mark Reynolds, pitchers Chris Young, Micah Owings and Tony Pena and outfielder Justin Upton.
He was an all-American at Stanford and participated in the 1996 Olympics.
Hinch inherits a team with a 12-17 record, a .414 winning percentage, following a 20-8 start last season.
The Diamondbacks are 15th in the National League in runs scored.
Hinch starts his new job Friday night when the Diamondbacks are home to the Washington Nationals.
Melvin was in his fifth season with Arizona and his overall record was 337-340.
Copyright 2009 by United Press International.