Injection drug use (IDU) has been a route for HIV transmission since the beginning of the epidemic. This review focuses on an apparent decrease in the proportion of IDU-related HIV/AIDS in Massachusetts, New York, Connecticut, and Rhode Island from 1999 to the present. Although there are differences in HIV/AIDS reporting requirements among these states, the dramatic reduction in the proportion of HIV and AIDS cases related to IDU is notable and is comparable to the 42% decline in HIV diagnoses among injection drug users reported by the CDC in other areas of the country.