We sought to describe virologic and clinical retention outcomes among a group of HIV-infected adolescents and young adults (AYA) newly established in an adult HIV clinic compared with matched HIV-infected adults. AYA demonstrated lower rates of HIV-1 virologic suppression and higher rates of HIV-1 viral rebound and loss to follow-up compared with adults. African American AYA had the lowest rates of virologic suppression and the highest rates of viral rebound. Adult providers should consider HIV-infected AYA, particularly African American HIV-infected AYA, to potentially be at high risk for poor clinical outcomes in adult care.