Although the incidence of measles has reached record low levels in the United States, measles continues to occur in young adults. No single public health measure can ensure immunity for young adults, as school immunization laws do for young children. Therefore, to eliminate measles in this age-group, clinicians must take the initiative to vaccinate or revaccinate patients. To facilitate containment of outbreaks of measles, clinicians should include measles in the differential diagnosis of any illness characterized by fever and a generalized rash and should promptly report these cases as suspected measles to local health departments, without waiting for laboratory confirmation. If the suspected case is indeed measles, a significant outbreak could be avoided long before the first laboratory results are known.