Alcohol consumption during methadone maintenance treatment (MMT) is among the common challenges in the addiction field. It is reported that alcohol overuse is closely related to the peripheral consequences of social health, however, in some studies, there are not enough reliable data for such a conclusion for drug addicts; as the measures of therapists about the quality of life (QOL) in alcoholusers indicate the relatively healthy daily performance of these patients The presence of a low number of foreign studies conducted on the relationship between quality of life (QOL) and alcohol consumption among the MMT patients and lack of any similar studies in Iran were the main motifs of the author of the present work to evaluate the relationship between alcohol consumption and QOL of MMT patients. This work is a cross-sectional analytical study through which the quality of life (QOL) ofpatient's subject to MMT without alcohol overdose was investigated. The statistical population of this work was all male 18- to 60-yearold patients under MMT process, who were selected among the patients referring to MMT educational health center of the Shafa in Rasht City in 2014.all participants were subject to alcohol consumption measure and QOL tests using MacAndrew alcoholism scale (MAC-R) and short form 36-item (SF-36) QOL measurement questionnaire, respectively. The study population of the present work was 190 patients under MMT process who were divided into two control and alcoholic groups. The mean and standard deviation for the age of participants in alcoholic and control groups were 37.65 ± 7.49 and 36.02 ± 7.95 years, respectively. The findings also show that, based on the revised alcoholism MacAndrew scale, the average score of the participants is 27.76 ± 5.19. Based on this scale, 21.1, 30.5, and 48.4% of the participants had a slight, average, and severe alcohol overdose problem. The results obtained from SF-36 questionnaire indicate that the mean and standard deviation of the alcoholic and control groups are 45.0 ± 22.4 and 35.2 ± 22.8, respectively. The present study showed that methadone dosage in MMT process has a high predictive value in (quality of life) QOL determination. Hence, the careful regulation of methadone dosage with patient needs, as well as measuring the QOL subscales in MMT patients (particularly for those with the daily methadone dosage above 40 mg) and teaching the required scales for improving the low subscales are recommended for preventing symptoms such as consumption relapse, treatment interruption, and the communication problems related with QOL for the participants of this group.