The purpose of this study was to investigate patterns of prenatal care use among urban and rural Hispanic women in San Diego County, California. A cohort study of Hispanic women delivering at one of five San Diego County hospitals between July 1991 and January 1992 was conducted (N = 587). Data were collected by in-person interview and medical record abstraction. Logistic regression was used to identify variables associated with late entry into prenatal care, while simultaneously adjusting for important confounding variables. Three factors were found to be significantly associated with late entry into prenatal care. Women who resided in urban areas were two times more likely to enter prenatal care late as compared to women who lived in rural areas (odds ratio = 2.11; 95% confidence intervals (CI) = 1.12, 4.0). Women who reported not having initially "wanted" the pregnancy were 2.2 times more likely to enter prenatal care late (95% CI = 1.05, 4.59). The risk of entering prenatal care late increased by 20% for each additional barrier to care that was reported (95% CI = 1.09, 1.34). Results indicate that timely entry into prenatal care may be improved among San Diego Hispanic women by targeting specific barriers to prenatal care identified in this study and by providing greater family planning assistance to this population to decrease unwanted pregnancies.