This study examines the association between mental health, substance abuse and family factors and medical treatment adherence in 128 HIV-infected ethnic minority mothers. Data were collected by structured individual interviews for a longitudinal study on psychosocial factors influencing HIV medical treatment adherence. Medical chart data were collected on CD4 cell counts and HIV RNA viral load. Results of baseline interviews are presented herein. The majority of participants were African American (58%) and Latina (35%) single parents (70%) living below the poverty line. Nearly 50% of the women met screening criteria for a current psychiatric disorder, and 25% for a substance abuse disorder. Two-thirds of the women were currently on antiretroviral medication; 20% of them reported missing pills in the past two days. Presence of a psychiatric or substance abuse disorder and parenting stress were the strongest correlates of non-adherence to antiretroviral medication. Less HIV disclosure to children and single parent status were associated with missing medical appointments. The results support the need for integrated mental health, substance abuse and medical treatment for HIV-infected women.