This prospective study of cats diagnosed with chronic renal failure compared the survival time of cats fed either a regular cat food or a low phosphorus/ low protein diet (with or without phosphate binders) from diagnosis onwards. 29 cats accepted the veterinary diet, whereas compliance was not achieved in the remaining 21. At diagnosis, both groups of cats were matched in terms of age, bodyweight and blood and urinary parameters. Feeding the veterinary diet was associated with reduced plasma phosphate and urea concentrations and reduced plasma PTH concentrations. Median survival in cats fed the restricted diet was significantly longer than the control group (633 versus 264 days).