By focusing on the most probable mode of exposure, HIV/AIDS surveillance systems have historically been largely effective at describing how HIV is acquired in the United States. However, this analysis demonstrates that the use of the current Centers for Disease Control and Prevention (CDC) risk hierarchy may be inadequate to describe recent trends in HIV acquisition by women, who continue to make up a greater number and proportion of new cases of HIV infection and AIDS both in Michigan and nationally. The authors suggest two changes to the current risk hierarchy to increase the accuracy of describing HIV acquisition: (1). a dual injecting drug users/heterosexual category; and (2). a presumed heterosexual category. They also propose that currently collected information be more thoroughly analyzed to better describe subsequent transmission from HIV infected men to their uninfected female sex partners.