Background: Acute respiratory distress syndrome (ARDS) diagnosis requires an invasive arterial blood sampling to reveal the PaO2and calculate the PaO2/FiO2 ratio. SpO2/FiO2 ratio has been proposed as a non-invasive alternative to identify oxygenation parameter in pediatric patients with ARDS. Objective: To evaluate sensitivity and specificity of SpO2/FiO2 as an oxygenation parameter to detect ARDS. Methods: We conducted a cross-sectional at the Pediatric Emergency and Intensive Care Department, Sanglah General Hospital, Denpasar, Bali. The inclusion criteria were 1 month to 12 years old patient admitted to our PICU and diagnosed with mild or moderate to severe ARDS based on blood gas analysis which fulfilled Berlin definition (ESICM 2012). The exlusion criteria were patient with a chronic lung disease and or a cyanotic heart disease. We collected SpO2/FiO2 ratio and calculated its sensitivity and specificity in detecting ARDS. Results: There were 124 patients enrolled. The most common diagnosis was diseases in respiratory system (62.1%). Based on ROC analysis to determine SpO2/FiO2 ratio needed to detect moderate to severe ARDS, the AUC was 0.76 (95%CI 0.677-0.843) and the cut-off point for SpO2/FiO2 ratio was <196. The sensitivity was 88.5% (95%CI 77.8-95.3) and specificity 44.4% (95%CI 31.9-57.5). Conclusion: SpO2/FiO2 ratio can be used as an oxygenation parameter in ARDS patients.