Yes cranberry juice is good for your kidneys and for preventing Urinary tract infections.
The cranberries contain a compound that help keep bacteria from sticking to the wall of the urinary tract.
It's recommended that you drink at least one glass of cranberry juice per day to prevent kidney disease and urinary tract infections.
Cranberry juice is a very healthy drink that should be drank at least once daily to really reap the health benefits of the cranberry juice.