Wu S et al. - Report a 43-year-old man diagnosed with acquired immunodeficiency syndrome and pulmonary TB coinfection. His symptoms, sputum quantity, and chest radiologic appearance improved markedly after 3 weeks of antituberculous therapy, and HAART was initiated on the fourth week. However, acute abdomen with peritoneal signs resulting from the established tuberculous peritonitis developed on the seventh day of HAART.