In these cases, HIV infection occurred following skin or mucous membrane exposures, and other risk factors for HIV infections could not be identified. The exact route of transmission in these cases is unknown. These cases are in addition to six previously reported cases of HIV infection following exposure to infected blood, four of which involved needle-sticks. Previous studies of workers with percutaneous and mucous membrane exposures to blood and body fluids of acquired immune deficiency syndrome patients suggest that the risk of transmission by this means is very low. While these cases are rare events, they reemphasize the need for healthcare workers to adhere rigorously to existing infection control recommendations. 2 notes and 16 references.