Effective renal plasma flow was measured in acute spinal cord injury patients for up to 10 years after injury to determine the extent of renal deterioration in these patients and to identify the factors associated with a loss of renal function. The over-all mean decrease in effective renal plasma flow for all patients as a whole was 4.5 ml. per year. Factors associated with a statistically significant reduction in effective renal plasma flow included age, gender, renal calculi, quadriplegia, and a history of chills and fever. Other factors examined but not found to be statistically significant included years since injury, presence of severe decubiti, bladder calculi, bacteriuria and extent of injury. This study suggests that renal function usually can be preserved in spinal cord injury patients if the treatable risk factors are managed properly.