Objective: To investigate the efficacy of insulin therapy in preventing cystopathic changes in diabetes using a rabbit model. Materials and Methods: Twenty-four New Zealand white rabbits were studied in three groups: eight in group 1 as control, eight in group 2 with diabetes by administration intravenously alloxan hydrochloride and eight in group 3 administered insulin therapy after induction of diabetes. Urodynamic investigations were carried out in three groups at the end of 8 weeks. Tissue sections prepared from all groups were studied histologically. Results: Bladder capacity and compliance increased in diabetic non-treated group. There was no significant difference between the control group and the diabetic group treated with insulin. The neuropathic changes were observed in the diabetic group, whereas the findings of the histological study were similar in the control and in the insulin treatment group. Conclusions: This animal model indicates that insulin therapy can prevent or delay urodynamic and histopathological changes in diabetes mellitus. These results must be supported by in vitro pharmacological studies.