On a Ugandan national amateur team trip to the
United States, Ouma decided to stay to undertake a career as a professional boxer to support his family in Uganda. Ouma later won the
International Boxing Federation (IBF) Junior Middleweight world title. Ouma is a former champion and top-level contender in the
Light Middleweight division. He has quality wins against Jason Papillion,
Juan Carlos Candelo, and
Verno Phillips, his second win against whom earned him the
IBF Light Middleweight title. Ouma successfully defended his championship with a twelve-round unanimous decision against
Kofi Jantuah of
Ghana. Ouma later lost this title in a unanimous decision defeat against
Roman Karmazin, a bout in which Ouma was put to the canvas twice. It was only the second defeat of his career. Since the Karmazin bout, Ouma has remained active in the Light Middleweight division, earning three wins, two by knockout. On May 6, 2006, Ouma defeated
Marco Antonio Rubio by split decision despite being knocked down in the first round. Ouma returned to the ring with an impressive win over undefeated fellow southpaw
Sechew Powell August 5, 2006. Powell is from Brooklyn, NY and the fight took place at the Theatre of
Madison Square Garden. The official scorecards were 90-100, 93-97, and 94-96 all in favor of Kassim Ouma by unanimous decision. Ouma lost the middleweight title shot against
Jermain Taylor on Dec. 9, 2006. Taylor's power and well-timed clenches kept Ouma from throwing as many punches as he usually does. Despite absorbing a large number of extremely hard shots, Ouma did not go down. The fight went the full 12 rounds, and Ouma lost by unanimous decision. The judges scored the fight 118-110, 117-111 and 115-113 for Taylor who was at home in
Little Rock, Arkansas. After the Taylor fight Ouma lost back to back close decisions to Saul Roman in October 2007 and Cornelius Bundrage in March 2008. On September 25, 2010, Ouma stopped
Joey Gilbert in the 6th round of their 10-round bout for the vacant NABA middleweight title at the
Grand Sierra Resort in Reno, Nevada. ==Personal life==