Diabetes mellitus causes remodeling of the urinary bladder, the natural history of which is poorly understood. In this study, we examined the temporal remodeling of the bladder in diabetic and diuretic rats. Male SD rats were divided into 3 groups: streptozotocin-induced diabetics, 5% sucrose-induced diuretics, and age-matched controls. Micturition and morphometric characteristics were evaluated using metabolic cages and examination of the bladder by light microscopy 4 days and 1, 2, 3 or 9 weeks after induction. Digital image analysis was used to quantify equatorial cross-sectional areas of bladder tissue and lumen, as well as relative content of the three primary tissue components: smooth muscle, urothelium, and collagen. Both diabetes and diuresis caused significant increases in fluid intake, urine output and bladder weight. In both groups, progressive increases were observed in the lumen area from 4 days to 3 weeks, and in the wall area from 2 to 3 weeks, after induction. The wall thickness decreased within the first 2 weeks in the diabetic and diuretic rats, but returned to control thickness at 3 and 9 weeks. As a percentage of the total cross sectional area, smooth muscle area increased, urothelium area was unchanged, and collagen area decreased in the diabetic and diuretic rats since 2 to 3 weeks compared with controls. In conclusion, diabetes and diuresis induced similar bladder remodeling. Diabetes-induced diuresis caused adaptive physical changes of the rat bladder by 4 days, and remodeling by 2 to 3 weeks after induction, which remained stable from 3 to 9 weeks.