Normal pregnancy is associated with an increase in uteroplacental blood flow in part due to growth and remodeling of the maternal uterine vasculature. In this study, we characterized the effect of diabetic pregnancy on vascular growth of the maternal uterine vasculature and on the passive mechanical properties of the uterine resistance arteries. Diabetes was induced in pregnant rats by injection of streptozotocin and confirmed by development of hyperglycemia. Fetuses of diabetic rats were significantly smaller and placentas larger compared to controls. Pregnancy-induced axial elongation of the mesometrial uterine vasculature was not altered by diabetes. Vascular wall thickness was unchanged between groups. Wall distensibility was increased and the rate constant of an exponential function fitted to stress-strain curve was significantly reduced demonstrating decreased wall stiffness in diabetic uterine radial arteries compared to controls. We conclude that experimental diabetes in rat pregnancy does not compromise the growth of maternal uterine vasculature but alters passive mechanical properties of the uterine radial arteries.