Background: Obstructive sleep apnea (OSA) is the most prevalent variation of sleep-disordered respiration. Recurrent compression of the upper airway during sleep, which results in oxygen desaturation and subsequent arousals from sleep, is the hallmark of OSA. This study aimed to determine the existence of a correlation between OSA and serum uric acid and lactate levels as potential indicators of tissue hypoxia, as well as their correlation with disease severity. Methods: This prospective cross-sectional study included 50 patients with sleep related breathing disorders who were attend at sleep study unit, Chest department at Benha University Hospital. Results: There was a significant positive correlation between serum uric level after sleep and apnea–hypopnea index (AHI) and OSA classification, lactate after sleep, Epworth sleepiness scale (ESS),and oxygen desaturation index. There was a significant negative correlation between serum uric level after sleep and mean SpO2, lowest SpO2 and total sleep time. There was a significant positive correlation between lactate level after sleep and AHI and OSA classification, ESS and oxygen desaturation index. There was a significant negative correlation between lactate level after sleep and mean SpO2, lowest SpO2 and total sleep time. The serum uric acid and lactate after sleep was significantly higher compared to before sleep (P