Objective: This study aimed to evaluate the effect of colectomy in children with ulcerative colitis (UC). Methods: The effects of colectomy on clinical and laboratory findings and the complications of the colectomy were evaluated retrospectively. Results: Colectomy was performed in 18 children; the mean age was 8,02 +/- 5,66 years old; 66,6% of the patients were the boys. In 16 children, the indication was a poor response to medical therapy; dysplasia in one patient and toxic megacolon and bleeding in another patient. Cyclosporine and/or infliximab were used in 13 patients as step-up or rescue therapies before colectomy. Ileoanal anastomosis was performed in 13 patients, ileal pouch and ileoanal anastomosis were performed in 2 patients, Hartmann pouch and subtotal colectomy with ileostomy were performed in 2 patients, and subtotal colectomy was performed in one patient. Although there was no statistical difference; Z-scores for the weight, the height, and the body mass index improved within one year, after colectomy. Hemoglobin level increased, and leukocytes, C-reactive protein, and erythrocyte sedimentation rate serum levels decreased within one year, after colectomy. The immunosuppressive drugs were discontinued after the colectomy in all, except two patients. The most common complications were fecal incontinence and frequent defecation. Conclusion: The most common indication for colectomy was a poor response to medical therapy. Colectomy improved clinical and laboratory findings by alleviating inflammation and restored growth and development of the children. It has reduced the use of immunosuppressive drugs which have significant side effects. The complications that have seen after surgery were tolerable.