OBJECTIVES Although sexually transmitted diseases (STDs) cause tremendous health and economic burdens in our society, awareness and knowledge regarding STDs remain poor among health care providers. To examine missed opportunities for STD-related counseling, diagnosis and treatment, we investigated how frequently U.S. adults reported being asked about STDs by their health care providers during routine checkups. METHODS We analyzed the responses of 3390 adults aged 18-64 who reported having a routine checkup during the past year in the 1994 U.S. National Health Interview Survey (NHIS), a nationally representative survey. We used a logistic model to determine factors that were independently associated with the likelihood of being asked about STDs during the checkup. RESULTS Only 28% (+/-0.9%) of respondents reported being asked about STDs during their last routine checkup. Persons were significantly more likely (p<0.05) to be asked about STDs if they were aged under 45, male, single, had a household income under the federal poverty level, or were insured by a health maintenance organization, public coverage or by no plan rather than by a fee-for-service arrangement. CONCLUSIONS Only about one quarter of U.S. adults reported being asked about STDs during routine checkups. Routine checkups in which these issues are not discussed may represent missed opportunities for STD prevention. Persons presenting for routine care can be counseled, screened and, if infected, can be treated. Interventions are needed at the patient, provider, and community levels to increase the opportunities to assess STD risk, to counsel, to diagnose, and to treat infections during routine checkups.