Official release from Montreal Impact.
Per club and Major League Soccer policy, terms of the agreement will not be disclosed.
The 28 year-old American midfielder, born in Bosnia-Herzegovina, becomes the fourth player to sign with the Impact for its inaugural season in MLS, after Colombian defender Nelson Rivas, French midfielder Hassoun Camara and American goalkeeper Evan Bush.
"I'm extremely happy to be joining the Impact family for Major League Soccer," said Ubiparipovic. "I am looking forward to helping this team make the transition into the new league, and also start working on winning championships."
"As a club, we are excited to have come to terms with Sinisa," said Impact head coach Jesse Marsch. "With his MLS experience and success in the NASL this year, we think he will be an important piece moving forward for our move in MLS."
In 2011, Ubiparipovic finished the season as the Impact's leader in assists and third leading-scorer, registering three goals and four assists for 10 points in as many games, including eight as a starter. Ubiparipovic, who had joined the team on Aug. 2, was named the club's Newcomer of the Year.
Previously in his career, Ubiparipovic played with the New York Red Bulls of Major League Soccer, from 2007 to 2010. He registered two goals and five assists in 69 regular season games, including 33 starts.
He also played six playoff games with Red Bulls. In 2008, he helped New York reach the MLS Cup final, after starting all four playoff games. He also took part in two CONCACAF Champions League games in 2009.
A graduate of the University of Akron, he was drafted in the third round, 33rd overall, by the Red Bulls in the 2007 MLS SuperDraft.