To investigate clinical course and outcome of dengue with acute respiratory failure (ARF), and to identify related risk factors for acquiring ARF in dengue, we retrospectively studied 11 dengue patients with ARF. From June to December 2002, a total of 606 adult patients were diagnosed as having dengue. Eleven (1.8%) of 606 dengue patients had complications of ARF. The main causes of ARF were sepsis (n = 6, 54.5%) and upper gastrointestinal (UGI) bleeding (n = 3, 27.3%). The mortality rate was 72.7% (n = 8). Additionally, univariate analysis showed that age, dyspnea, cough, prothrombin time, activated partial thromboplastin time, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine, albumin, renal insufficiency, acute renal failure, acute hepatic failure, UGI bleeding, and combination bacterial infection were significantly predictive variables associated with dengue patients with ARF.