Only in 1990, Provincial Osorno finally won the second division title to win promotion to the Primera Division for the first time, under the direction of manager Guillermo Yavar, but they finished near the bottom of the table and were relegated in 1991.
This time the club managed to stay in the top flight until 1998, with regular campaigns, with the exception of 1996, when, under the direction of manager Oscar "Cacho" Malbernat they finished 6th.