A 31-year-old woman, heroin addict since ten years, and infected by the human immunodeficiency virus (HIV) since one year, was admitted to the intensive care unit for respiratory failure (PaO2 = 40 mmHg and PaCO2 = 14.8 mmHg, despite breathing pure oxygen). She had been followed up for 6 months for increasing dyspnoea due to chronic cor pulmonale for which no satisfactory explanation had been put forward. Artificial ventilation with 8 cmH2O positive end-expiratory pressure and 100% oxygen was completely inefficient. She died within a few hours. Postmortem lung biopsy revealed talc particles within interalveolar walls and alveolar macrophages as well as the expected alterations in blood vessels. Pulmonary hypertension due to talc microemboli is a well-known cause of respiratory failure in heroin addicts. Such a diagnosis should not be overlooked in a patient infected with HIV. Respiratory failure may not be only due to opportunist infections, or tumours related to the HIV infection.