Although the pulmonary complications of advanced human immunodeficiency virus (HIV) infection have been well described, there is little information on respiratory manifestations of earlier disease. This report describes the respiratory disorders diagnosed over an 18-month period in a cohort of persons with or at risk for HIV infection with variable immunologic status. Cohort members were followed routinely and evaluated for respiratory disease by standard diagnostic algorithms. The 18-month incidence of each respiratory diagnosis was determined, and for frequent diagnoses, incidence by transmission category, location of residence, smoking status, CD4 count, and performance score at entry were compared. The most frequent respiratory diagnoses in HIV-seropositive cohort members were common to the general population: upper respiratory infection (33.4%), acute bronchitis (16.0%), acute sinusitis (5.3%), and bacterial pneumonia (4.8%). Pneumocystis carinii pneumonia occurred in 3.9%. Ambulatory respiratory illnesses were reported frequently regardless of immunologic status. The rates of P. carinii pneumonia and bacterial pneumonia were significantly greater in cohort members with entry CD4 counts < 250. Bacterial pneumonia occurred more frequently in injecting drug users and in cohort members with entry Karnofsky scores < 90. Disease stage and demographic and exposure factors are important variables affecting the respiratory manifestations of HIV infection.