Nasal Continuous Positive Airway Pressure (NCPAP), one noninvasive treatment for respiratory failure, is highly effective, easy to apply and secure. The study was conducted to evaluate the effectiveness of nasal continuous airway positive pressure (NCPAP) in the treatment of respiratory failure due to pneumonia in children under 5 years old at the Saint Paul Hospital, 2. Evaluation of factors affecting treatment outcomes by NCPAP respiratory failure. The results showed that the success rate 73.6 percent, failure rate 26.4 percent, most success case focus on day 3 to day 5, the defeat focus on the first 3 days breathing NCPAP. The clinical symptoms of respiratory and blood gases improved after 6 hours of breathing NCPAP and maintained in the later time. Factors related to results of treatment for respiratory failure with NCPAP include: respiratory failure levels, PaO2, PaCO2 before NCPAP.