The recovery of renal function following release of urinary tract obstruction with advanced azotemia determines both the need for emergency dialysis in the early post-obstructive period and the long-term planning for chronic kidney disease management. A man with prostatic cancer who presented with 16 days of anuria and a serum creatinine (Scr) of 42.7 mg/dl but had evidence suggesting residual renal function was managed conservatively and reached a steady-state Scr of 1.6 mg/dl within 84 h of urinary bladder catheterization. Modeling of the decrease in Scr taking into account the decline in the body creatinine pool that existed prior to the release of the obstruction and the accumulation in body fluids of creatinine produced after the release of the obstruction suggested that recovery of the value of glomerular filtration rate corresponding to the steady-state Scr occurred at the release of the urinary obstruction. The case illustrates both the clinical factors that may lead to the decision to postpone dialysis in a patient presenting with extreme obstructive azotemia and a novel method of modeling the recovery of renal function after release of the obstruction.