Combined rupture of the medial collateral ligament, medial meniscus, and anterior cruciate ligament is common. Since O Donoghue described this combined injury in 1950, it has been referred to as O Donoghue's triad. But the rupture of the patellar tendon is a relatively uncommon form of injury, particularly in a young, well-conditioned athlete. Baker (1980) presented a case of O' Donoghue' s triad with a rupture of the patellar tendon. We present an unusual case of patellar tendon rupture associated with rupture of anterior cruciate ligament, medial collateral ligament, lateral collateral ligament and lateral meniscus. This case differs from Baker's case and has not yet been reported in the literature. The senior author performed arthroscopic partial menisectomy, patellar tendon repair by Matava's method and arthroscopic anterior cruciate ligament reconstruction, using the autogenous bone-patellar tendon-bone graft from the controlateral knee. The clinical results were good, and as far as the authors have reviewed, no report has been published about this rare injury. So we report this case with a review of the literature.