The present community-based study in Bogotá, Colombia, investigated risk assessment and preventive counseling practices of obstetrician/gynecologists (ob/gyn n = 34) and their impact on women's (n = 230) knowledge and risk behaviors. The data indicate that physician education has a significant and positive impact on women's knowledge and behavior. After controlling for sociodemographic variables, women instructed by their ob/gyn were 11 times more likely to correctly identify preventive measures (p = 0.0001) and high-risk sexual practices for the HIV/sexually transmitted diseases (STDs) transmission (4x; p = 0.05) and were less likely to engage in high-risk sexual practices (OR = 2; p = 0.05). Few ob/gyns (17%), however, assess risk behaviors and provide risk reduction counseling, and only 6% frequently encouraged HIV testing. These findings highlight the potential public health impact of ob/gyn physicians and underscore the need to increase their involvement in halting the HIV/STD epidemic in Colombia.