Bacterial and viral sexually transmitted infections (STIs) are common in the US. Approximately 20 million new cases of bacterial or viral STIs occur each year in the US, and about one-half of these cases occur in persons aged 15 to 24 years. 1,2 Rates of chlamydial, gonococcal, and syphilis infection continue to increase in all regions. 2 Sexually transmitted infections are frequently asymptomatic, which may delay diagnosis and treatment and lead persons to unknowingly transmit STIs to others. Serious consequences of STIs include pelvic inflammatory disease, infertility, cancer, and AIDS. Untreated STIs that present during pregnancy or birth may cause harms to the mother and infant, including perinatal infection, serious physical and developmental disabilities, and death. 3,4 USPSTF Assessment of Magnitude of Net Benefit The US Preventive Services Task Force (USPSTF) concludes with moderate certainty that behavioral counseling interventions reduce the likelihood of acquiring STIs in sexually active adolescents and in adults at increased risk, resulting in a moderate net benefit. See the Figure and Table 1 for more information on the USPSTF recommendation rationale and assessment. For more details on the methods the USPSTF uses to determine the net benefit, see the USPSTF Procedure Manual. 5 IMPORTANCE Approximately 20 million new cases of bacterial or viral sexually transmitted infections (STIs) occur each year in the US, and about one-half of these cases occur in persons aged 15 to 24 years. Rates of chlamydial, gonococcal, and syphilis infection continue to increase in all regions. Sexually transmitted infections are frequently asymptomatic, which may delay diagnosis and treatment and lead persons to unknowingly transmit STIs to others. Serious consequences of STIs include pelvic inflammatory disease, infertility, cancer, and AIDS. OBJECTIVE To update its 2014 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a review of the evidence on the benefits and harms of behavioral counseling interventions for preventing STI acquisition. POPULATION This recommendation statement applies to all sexually active adolescents and to adults at increased risk for STIs. EVIDENCE ASSESSMENT The USPSTF concludes with moderate certainty that behavioral counseling interventions reduce the likelihood of acquiring STIs in sexually active adolescents and in adults at increased risk, including for example, those who have a current STI, do not use condoms, or have multiple partners, resulting in a moderate net benefit. RECOMMENDATION The USPSTF recommends behavioral counseling for all sexually active adolescents and for adults at increased risk for STIs. (B recommendation)