Objectives: We compared the functional and cosmetic results of lateral and medial approaches in the surgical treatment of type III supracondylar humeral fractures in children. Methods: The study included two groups in which type III supracondylar humeral fractures were treated using either lateral (12 boys, 8 girls; mean age 7.2 years; range 4 to 12 years) or medial (16 boys, 4 girls; mean age 7.4 years; range 3 to 11 years) approaches and internal fixation. Functional and cosmetic results were assessed according to the criteria proposed by Flynn et al. The mean follow-up periods were 19.8 months (range 8 to 30 months) and 19.5 months (range 12 to 27 months) in the lateral and medial approach groups, respectively. Patient satisfaction was also inquired regarding the site of the incision scar. Results: In the lateral approach group, functional results were excellent in 18 patients (90%), good in one patient (5%), and fair in one patient, while cosmetic results were excellent in 19 patients (95%) and good in one patient. In the medial approach group, 19 patients (95%) had excellent and one patient (5%) had good functional results, while all the patients had an excellent cosmetic result (p>0.05). Complications were seen only in the lateral approach group, including transient ulnar nerve palsy in one patient, and cubitus varus deformity due to limited range of motion in another. The satisfaction rates concerning the site of the incision scar were 25% and 70% in the lateral and medial approach groups, respectively. Conclusion: Although no significant differences were found between the lateral and medial approaches in terms of functional and cosmetic results, the medial approach may be more convenient due to a lower risk for ulnar nerve injury and to a greater acceptability of the medial incision scar on the part of the patients.