Acute kidney injury (AKI) necessitating renal-replacement therapy has been associated with high mortality rates in critically ill patients. Usual methods to study AKI encompass the assessment of serum and urine biomarkers. Hypoxia is a major pathophysiological feature of AKI, which necessitates continuous bedside monitoring of renal tissue oxygenation in intensive care unit (ICU) patients. Research has made continuous bladder urine oxygen pressure (PuO2) monitoring possible in humans. Although the value of bladder PuO2 does not represent an absolute value of medullary tissue oxygen pressure (Po2), bladder PuO2 can be considered a window into the renal medullary oxygenation. Bladder PuO2 can be monitored by using probes with oxygen sensors inserted into the urinary bladder. Additionally, PuO2 can be measured manually by using a blood gas analyzer machine. PuO2 monitoring can be potentially helpful in early diagnosis and/or prevention of AKI and guide therapeutic interventions aimed at improving renal oxygen delivery in those patients.