Dengue hemorrhagic fever (DHF) is caused by dengue virus. Patients with DHF grade 3-4, termed Dengue Shock Syndrome (DSS), may develop acute respiratory failure after initial fluid resuscitation. Previously, these patients were treated with oxygen on a nasal cannula, or if necessary with tracheal intubation and mechanical ventilation. In the present prospective randomized study, we compared the effectiveness of oxygen treatment administered by a face mask vs. nasal continuous positive airway pressure (NCPAP). Morbidity, mortality, and supportive treatment was evaluated. Thirty-seven patients with DSS complicated by respiratory failure were enrolled. On admission and after 30 min of treatment, clinical and paraclinical data were obtained. Chest X-ray revealed pleural effusion in 92 per cent and showed interstitial oedema in 33 per cent. After 30 min of treatment the respiratory rate decreased significantly in the NCPAP group (p < 0.05), while SaO2 and PaO2 increased in both groups (p < 0.01). However, subsequently a significant difference of unresponsiveness to treatment between the oxygen mask group and the NCPAP group (13/19 vs. 4/18,p < 0.01) was noted. Complications of NCPAP or oxygen mask treatment were not documented. We conclude that NCPAP is useful in improving the management of acute respiratory failure in children with DHF/DSS in dengue-endemic areas.