An 85-year-old man presented with bilateral leg edema and urinary incontinence. Abdominal examination revealed a severely distended bladder. Venous duplex of the legs demonstrated monophasic waveforms bilaterally, suggesting obstruction of proximal lower extremity veins. Relief of urinary obstruction was associated with the prompt return of normal respiratory variation of flow in the veins and improvement of leg swelling. Non-thrombotic obstruction of the proximal veins of the lower extremities by a severely enlarged urinary bladder is an infrequent yet potentially reversible cause of lower extremity edema. Subtle clues in the Doppler waveforms of an otherwise normal lower extremity venous duplex examination are crucial in establishing this diagnosis.