This prospective, cross-sectional study sought to assess the spectrum of HIV-associated complications and disease stage among individuals presenting for first-time care in Phnom Penh, Cambodia between November 2001 and September 2002. One hundred patients participated in this study. All study participants presented with advanced stages of HIV disease. Seventy-four percent of the subjects had CD4 cell counts <50 cells/mm3. Tuberculosis was the most common AIDS-defining illness among participants, with a prevalence of 43%. A spectrum of other opportunistic infections, including cryptosporidiosis (13%), severe bacterial infections (12%), cryptococcosis (12%), and Pneumocystis jiroveci pneumonia (10%), was identified. These findings underscore the need for widespread HIV treatment and prevention in this setting. Increased screening for HIV and routine health maintenance for those infected are urgently needed in order to facilitate management of both opportunistic infections and the secondary prevention of HIV infection.