Objective: Carbon monoxide poisoning is an important cause of morbidity and mortality all over the world. In our study, it was aimed to determine the clinical and laboratory parameters that may be effective in deciding the need for hyperbaric oxygen therapy in the management of cases. Materials and Methods: From January 2012 to the end of December 2019, 83 patients who applied to a university hospital pediatric emergency department in İstanbul with the diagnosis of carbon monoxide poisoning were included. Demographic characteristics, carbon monoxide source, exposure duration, treatment approach, physical examination findings, Glasgow Coma Score, laboratory results, electrocardiogram, cranial imaging, and chest x-ray were evaluated from the records. Results: The median age of the patients was 56 (37.0-100.0) months and 48 (57.8%) of them were male. The median time of exposure to carbon monoxide was 5.0 (0.5-3.0) hours in those who received hyperbaric oxygen therapy and was significantly higher than those who received normobaric oxygen therapy (P < .001). Myocardial ischemia, chest pain, pulmonary edema, and renal failure were not detected in any of the cases. The median lactate level was detected as 1.5 (1.0-2.15) mmol/L in those who received normobaric oxygen therapy and 3.7 (3.17-4.62) mmol/L in those who received hyperbaric oxygen therapy, and the difference between them was statistically significant (P < .001). Conclusions: A guideline containing precise clinical and laboratory parameters for hyperbaric oxygen therapy in children has not been developed yet. In our study, carbon monoxide exposure duration, carboxyhemoglobin levels, neurological symptoms, and lactate levels were found to be guiding parameters in determining the need for hyperbaric oxygen therapy.