The purpose of this study is to retrospectively review the clinical, radiographic and laboratory characteristics, the therapy and evolution of sinusitis in HIV-infected patients hospitalized between January 1, 1985 and July 31, 1994. We have observed 65 cases of sinusitis in 58 HIV-infected patients (77.6% classified as group C). Forty-five of 65 cases (69.2%) showed radiographic evidence of acute sinusitis; the remaining 20 cases (30.8%) showed chronic sinusitis. In 61 cases (93.8%) there were symptoms related to sinusitis. In 61 sinusitis cases antibiotics were administered. Although the majority of patients responded at least partially to antibiotic therapy, a complete resolution of clinical and radiographic signs was observed in only 47.4% of acute sinusitis cases. No resolution was observed in chronic sinusitis after treatment stop. Sinusitis appears to occur quite frequently in HIV-infected patients, is often related to non-specific symptoms, may be recurrent and is commonly refractory to treatment.