The agreement, which was reached last week, lasts through the 2016 season. In addition to the CBA, the MLBPA's Executive Board voted to approve the Joint Drug Agreement and Benefit Plan Agreement.
The votes were unanimous, the union said Thursday.
"The board's decisive action here is a culmination of the consistent involvement of the players during this round of bargaining," MLBPA Executive Director Michael Weiner said in a statement.
"Ratification comes as no surprise, as players have been engaged heavily throughout the process -- constructing proposals, formulating strategy and participating in negotiating sessions."
Baseball was able to quickly put together a five-year CBA, unlike its counterparts in the NFL, which had a 4 1/2-month lockout prior to this season, and the NBA, which is ending a five-month lockout this week.
Among key aspects of the MLB agreement are an expansion of playoffs by one team in each league, implementation of blood testing for Human Growth Hormone and an increase in the minimum salary for major-league players to $480,000 in 2012.