Previous long-term studies have shown good outcomes for most patients after in situ pinning of slipped capital femoral epiphyses (SCFE). However, concern is growing about the effects of leaving the epiphysis in a nonanatomic position. We undertook a retrospective study to carefully document patient-reported outcomes and need for additional surgery after in situ pinning of SCFE. Further, we sought to determine the risk factors for persistent pain and dysfunction after in situ pinning. Between 1965 and 2005, 146 patients (176 hips) with SCFE underwent in situ pinning at a tertiary referral center. Medical records and radiographs were reviewed for slip characteristics and need for subsequent surgery. Patient-reported outcome measures were collected by mailed survey. Mean follow-up was 16 years (range, 2 to 43 y). Twenty-one hips (12%) underwent reconstructive surgery for persistent symptoms, including femoral osteotomy (11), surgical hip dislocation (2), and total hip arthroplasty (8). Mild slips, as well as moderate and severe slips, were treated with reconstructive surgery, including total hip arthroplasty. Of the remaining hips, 33% were painful with a mean overall visual analog score of 2.4 (range, 0 to 10). Mean outcome scores were as follows: Harris Hip Score 90 (max. 100); Hip Dysfunction Osteoarthritis Outcome score 411 (max. 500); UCLA Activity Score 8 (max. 10); and Marx Activity Score 5 (max. 16). Reconstructive surgery was performed in 12% of hips. Patients with mild, moderate, and severe slips underwent arthroplasty for degenerative changes. Persistent mild pain was common in one third of patients treated with in situ pinning. Level IV, therapeutic study, case series.