AIM: To evaluate the outcome of 20 children with moderate-severe slipped capital femoral epiphysis (SCFE) with open physes, treated by the modified Dunn’s procedure, as regards: intraoperative fi ndings, clinical and radiographic outcomes, and postoperative complication rate. PATIENTS AND METHODS: A prospective study was executed, between 2012 and 2016, for treating moderate-severe SCFE with modified Dunn procedure in 20 hips of 20 patients, with a mean age of 13.6 ± 3.4 years (range: 10 - 16.5 years). Seven cases wereunstable SCFE. We excluded mild SCFE, endocrinopathy and renal cases. RESULTS: The mean follow-up was 19 ± 9.2 months (range: 12 - 36 months). Radiologically. all parameters showed significant improvement; with the mean slip angle corrected from 61º± 14.4 preoperatively to 10º ± 10.1 postoperatively, the mean alpha angle corrected from 90.2 ± 21º preoperatively to 49.1 ± 8º postoperatively and the mean femoral neck length difference was 8.1 ± 6 mm. Functionally, the mean Harris hip score (HHS) was 86.2 ± 9.6 and the Heyman and Herndon score was excellent-good in 15 cases (75%), fair in two, poor in two and failed in one. Postoperative major complications occurred in only two cases (10%); AVN in one and secondary FAI in another case. CONCLUSIONS: Modified Dunn’s procedure is an effective and safe treatment for moderate-severe SCFE, achieving better anatomical and functional outcome, with a reasonable complication rate.