The treatment of 19 congenitally dislocated knees in 11 patients is reviewed. The knees were subdivided into genu recurvatum, subluxation and dislocation. Nine knees were treated conservatively and ten surgically. A good result was obtained with conservative treatment if started before the age of three months; after this, surgery was likely to be required and was satisfactory if undertaken before two years of age. A successful surgical result was achieved with quadriceps lengthening. If the quadriceps tendon and the anterior cruciate ligament were divided, then only fair results were achieved. Untreated, patients developed stiff, unstable knees.