Point-of-care ultrasound (POCUS) of the kidneys and bladder is a critically important bedside diagnostic modality for the evaluation of patients in the intensive care unit (ICU), among whom there is a high incidence of acute kidney injury (AKI) and a high rate of urinary catheter use. Using POCUS, clinicians in the ICU can rapidly identify reversible causes of post-renal AKI, measure bladder volume more accurately, diagnose urinary retention, troubleshoot malfunctioning urinary catheters, assess for ureteral patency, or recognize signs of an obstructing renal stone in patients with urosepsis, any of which may change immediate management or warrant urgent procedural intervention. This chapter will describe how the intensivist can obtain such actionable information using point-of-care renal and bladder ultrasound.