A 24-year-old heterosexual male, HIV-infected intravenous drug addict, with necrotizing pneumonitis and empyema due to Streptococcus cremoris is presented. The patient had fever, severe dyspnea and chest pain. Chest roentgenogram demonstrated pleural effusion on the left side. A thoracocentesis revealed purulent exudate and S. cremoris was isolated. Fever and pleural effusion disappeared with penicillin and clindamycin therapy. The most likely source of the infection was ingestion of unpasteurized milk and cheese.