Toxoplasmosis is a serious opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). The lung is a major site of infection after the central nervous system. The aim of the study was to assess the polymerase chain reaction (PCR) and cell culture for the detection of Toxoplasma gondii. One hundred and thirty two human immunodeficiency virus (HIV)-infected patients with respiratory manifestations, who underwent fibreoptic bronchoalveolar lavage, were investigated. Detection of Toxoplasma gondii was compared using three techniques: Giemsa staining; polymerase chain reaction with specific primers derived from the P30 gene; and culture on the MRC5 cell line. Toxoplasma gondii was detected in the same four samples by all three techniques. We conclude that PCR adds little to conventional (and cheaper) tools already used to diagnose pulmonary toxoplasmosis.