Over 58 000 members of the US Army Reserve Components tested for human immunodeficiency virus (HIV) antibody had military or civilian medical occupations. The availability of HIV status and occupational information permits the assessment of prevalence and incidence of infection in this population. Levels of infection were not higher among women or among currently married men with medical occupations compared with those with nonmedical occupations. Prevalence and incidence were elevated among never-married men with either military or civilian medical occupations compared with never-married men with nonmedical occupations. Based on reported civilian occupation, male registered nurses and men with other medical occupations, excluding physicians and dentists, had a significantly higher prevalence of infection than men with nonmedical occupations. The patterns of infection suggest that the higher levels of infection found among never-married men with medical occupations may not be entirely due to occupational exposure. These findings may have applications in the design and interpretation of results of health care worker HIV surveillance programs.