Background: This study aimed to investigate the prevalence of domestic violence (DV) against women who are undergoing methadone maintenance therapy (MMT) and its related risk factors. Methods: This case-control study was conducted on 195 women who were under MMT and a control group consisting of 195 women who were not under it in the city of Zahedan from 22 May to 1 December 2019. Data were collected using a questionnaire for the measurement of violence against women and a sociodemographic questionnaire. In order to analyze the data, the t test, analysis of variance (ANOVA), Pearson’s correlation, and multiple regression analysis were used. Findings: In the case group, 67.2% of participants had experienced DV during the past year. In the control group, the prevalence was 78.5%. The rate of more than one occasion of DV was significantly higher in the group who were under MMT (P<0.05). The most common type of violence was mental abuse. Physical, sexual, and economic abuses were in the next ranks. Important predictors of DV, in order of importance, were: the women’s low educational level, smoking, income level, and polygamy (P<0.05). Conclusion: MMT is not a risk factor for DV. It seems that the rate of DV against women in Zahedan is very high. The prevalence of recurrent DV in women under MMT was higher than in the general population.