Of 12 cases of acute slipping of the capital femoral epiphysis (representing 11 patients), results were satisfactory in nine cases and poor in three cases at follow-up (in two of the three cases with poor results, reduction was lost postoperatively). Five of nine patients with prodromal symptoms were seen by a physician but were undiagnosed or untreated before the acute slipping. An additional patient had roentgenographic evidence of an early (asymptomatic) slipping capital femoral epiphysis one year before the acute slipping. Preferred treatment is gentle manipulation and fixation with multiple threaded pins, followed by crutch walking for three to four months. Spica casting is not recommended because of an increased incidence of acute articular cartilage necrosis and the possibility of late recurrence of slipping.