This study had the aim of prospectively analyzing the clinical and epidemiological characteristics that lead adult patients with HIV/AIDS to seek urgent medical care in the walk-in service of the teaching hospital of the Federal University of Minas Gerais. Over a one-year period, all admissions of adult patients with HIV were evaluated. There were 118 admissions involving 99 patients. Their mean age was 39.4 years. The male-to-female ratio was 1.35:1. The length of time from diagnosis to admission was most frequently 0-5 years (40.4% of the cases). Antiretroviral therapy was being regularly used among 56.8% of the admissions. The T CD4+ lymphocyte count was less than 200 cells/mm(3) in 45.7% of the patients. The most frequent complaints were increased body temperature, diarrhea, coughing and dyspnea. The respiratory tract was the region most affected. The most common opportunistic diseases were pneumocystosis, community-acquired pneumonia, diarrheal syndrome and oral candidiasis. The demand for admissions among HIV patients represented 2.8% of all admissions, with an average length of stay of 4.6 days. Most of the patients had low T CD4+ lymphocyte counts, and almost half of them were not taking highly active antiretroviral therapy. There was a tendency towards feminization. AIDS-related diseases continue to be the most frequent occurrences within our setting.