HIV and other sexually transmitted diseases exact an enormous toll on society in terms of economic resources expended, human suffering inflicted, and years of life lost. Prevention is the best means for curbing the STD epidemics because there are no cures or vaccines for many STDs Primary care physicians can play an important role in preventing the spread of HIV and other STDs by assessing patients for risky sexual behaviors and by providing risk reduction counseling. Although many prestigious organizations have called for physicians to provide these important preventive services, many US physicians are not currently doing so. Attempts to induce physicians to perform sexual risk assessments and provide risk reduction counseling must content with general barriers to providing preventive services and specific barriers to discussing risky sexual behavior with patients. The present four-year study proposes to test, in a controlled randomized trial, an intensive nine-month intervention that addresses many of the barriers to physicians' performance of sexual risk assessments and provision of risk reduction counseling. The purpose of the intervention is to improve the skills of primary care physicians so that they will perform these tasks quickly and routinely with all patients having target visits. Primary care physicians will be randomly assigned to a control or experimental group. Measurement of performance of sexual risk assessment and risk reduction counseling will occur at pretest, posttest, and nine-month follow-up. The primary outcome measure will be obtained by telephone interviews with patients after target visits with their physicians. During the nine-month intervention period, physicians in the experimental group will receive Practice-oriented Newsletters, will have a Medical Record Reminder System inserted in the medical charts of all patients receiving target visits, and will attend two segments of a Skills-based Course, separated by three months. The course will contain lectures, trigger videotapes, and role playing with patient instructors. This project has the potential to significantly impact physicians' practices in providing sexual risk assessments and risk reduction counseling. By helping all patients understand the ways in which they may be placing themselves at risk of contracting an STD, these preventive practices could play a role in containing the spread of AIDS and other STDs.