The U.S. Preventive Services Task Force (USPSTF) has issued recommendations on behavioral counseling to prevent sexually transmitted infections (STIs) and recommendations about screening for individual STIs. Clinicians should obtain a sexual history to assess for behaviors that increase a patient's risk. Community and population risk factors should also be considered. The USPSTF recommends intensive behavioral counseling for all sexually active adolescents and for adults whose history indicates an increased risk of STIs. These interventions can reduce STI acquisition and risky sexual behaviors, and increase condom use and other protective behaviors. The USPSTF recommends screening for chlamydia and gonorrhea in all sexually active women 24 years and younger, and in older women at increased risk. It recommends screening for human immunodeficiency virus (HIV) infection in all patients 15 to 65 years of age regardless of risk, as well as in younger and older patients at increased risk of HIV infection. The USPSTF also recommends screening for hepatitis B virus infection and syphilis in persons at increased risk. All pregnant women should be tested for hepatitis B virus infection, HIV infection, and syphilis. Pregnant women 24 years and younger, and older women with risk factors should be tested for gonorrhea and chlamydia. The USPSTF recommends against screening for asymptomatic herpes simplex virus infection. There is inadequate evidence to determine the optimal interval for repeat screening; clinicians should rescreen patients when their sexual history reveals new or persistent risk factors.