Introduction: Topical antimicrobials, such as clindamycin, are effective in the treatment of acne and azelaic acid, due to the lack of bacterial resistance, could be a useful alternative in topical treatment of acne. The aim of this study was to compare the effect of topical azelaic acid 20% with clindamycin 1% lotion for the treatment of acne. Method: This randomized clinical trial study was performed on 108 patients with mild and moderate acne. Patient were randomly assigned to one of the two groups of treatment with azelaic acid 20% cream (50 patients) or clindamycin 1% lotion (58 patients). The patients were evaluated by grading and lesion counting methods before treatment and one month and two months after the treatment. Results: The mean age of the patients in clindamycin group and azalic acid was 19. 6±3. 9 and 20. 3±4. 5 years, respectively (P=0. 41). The mean score of acne severity decreased after treatment according to grading and lesion counting methods (P0. 05) Conclusion: Result showed that the azelaic acid 20% topical cream was as effective as clindamycin 1% lotion for treating mild to moderate acne.