In a setting with a high prevalence of HIV we studied (i) the prevalence of pulmonary tuberculosis (PTB) and HIV; (ii) clinical and epidemiological characteristics of PTB; and (iii) the usefulness of standard procedures for diagnosing PTB. Of 509 consecutive outpatients evaluated on clinical suspicion of PTB in Addis Ababa, 33.0% were culture-verified as having PTB. PTB patients, non-TB patients and controls were HIV-1-positive in 57.1%, 38.5% and 8.3% of cases, respectively. Predictors for culture-verified PTB were age < 25 y, male gender and the presence of HIV and fever, whereas profound weight loss indicated HIV infection. Diagnosis of PTB based on clinical symptoms, sputum microscopy for acid-fast bacilli and chest radiography was sensitive (86.7%) but unspecific (64.1%). In HIV-positive patients both sensitivity and specificity were significantly lower (p < 0.05). HIV-related pulmonary infections are often misinterpreted as smear-negative PTB. HIV screening is therefore warranted not only in cases of verified TB but also as part of the diagnostic work-up in patients with respiratory symptoms suggestive of PTB. Also, increased awareness of, and improved diagnostic tools for, HIV-related pulmonary infections other than PTB are required, together with algorithms for patients with suspected PTB.