Background and objective: Oral isotretinoin is the only treatment that has an effect on all the major etiological factors involved in acne (Increased sebum production, alterations in microbial flora, hyperkeratinization of pilosebaceous duct, and inflammation). Considering complications and relative expense, several treatment regimens have been suggested. The objective of this study was to evaluate the efficacy of intermittent doses of isotretinoin in acne patients. Materials ad Methods: We made a quasi-experimental clinical trial in the acne patients without nodular and cystic lesions that were recalcitrant to conventional therapy. Therapeutic regimen included 0.5 mg/kg isotretinoin per day for a week every month; So we use 21 mg/kg as total dosage. Results: Acne severity decreased in entire patients at the end of treatment course. After six months follow up, recurrence rate was 19.3% and partially recurrence rate was 44%. Conclusion: It seems that intermittent isotretinoin treatment with a total dose of 21 mg/kg has led to good therapeutic results in patients without nodulocystic lesions.