OBJECTIVE:To determine the relationship of social support from partners and others to the adequacy of prenatal care and to the prenatal health behaviors of low-income women. DESIGN:Descriptive, correlational study using self-reports and medical record review. SETTING:Data were collected in five metropolitan prenatal clinics serving low-income women. PARTICIPANTS:Ethnically diverse, primarily single, low-income pregnant women (N = 101) between 28 and 40 weeks of pregnancy. MAIN OUTCOME MEASURES:Subjects completed the Norbeck Social Support Questionnaire, the Prenatal Health Questionnaire, and the Demographic/Pregnancy Questionnaire. RESULTS:Social support provided by the partner correlated positively with adequacy of prenatal care, whereas social support from others (excluding partner relationships) correlated positively with prenatal health behaviors. Professionals such as health care providers and counselors were not considered sources of social support by women. CONCLUSIONS:Nurses who work with low-income pregnant women in a variety of settings should assist partners in recognizing their potential positive contributions, teach women to communicate their expectations to their partners, acknowledge the importance of other family members as providers of social support, and when needed, refer women to programs that increase available social support.