We conducted a cross-sectional study to estimate the prevalence of domestic violence and identify the reasons for it among 400 married women aged 15-45 years in low socioeconomic areas in urban Karachi. Data were collected with a pretested questionnaire. The prevalence of verbal abuse was 97.5% by the husband and 97.0% by the in-laws; the prevalence of physical abuse was 80.0% and 57.5% by the husband and in-laws respectively. Financial issues were the commonest reason for domestic violence followed by infertility and not having a son. The prevalence of domestic violence in our sample of women is high. There is a need to address this problem with efforts from health workers, policy-makers, nongovernmental organizations and others.