Roger Federer is a Swiss former professional tennis player. He was ranked as the world No. 1 in men's singles by the Association of Tennis Professionals (ATP) for 310 weeks, including a record 237 consecutive weeks, and finished as the year-end No. 1 five times. Federer won 103 singles titles on the ATP Tour, the second most since the start of the Open Era in 1968, including 20 major men's singles titles, 28 Masters and six year-end championships. ATP world No. 1 from February 2, 2004 to August 17, 2008 — 237 weeks. Wiki link