The present study was designed to determine whether the properties of local Ca²⁺ release and its related regulatory mechanisms might provide insight into the role of sex differences in heart functions of control and streptozotocin-induced diabetic adult rats. Left ventricular developed pressure (LVDP), the rates of pressure development and decay (±dP/dt), basal intracellular Ca²⁺ level ([Ca²⁺]_i), and spatio-temporal parameters of [Ca²⁺]_i transients were found similar in male and female control rats. However, spatio-temporal parameters of Ca²⁺ sparks in cardiomyocytes isolated from control females were significantly larger and slower than in control males. Diabetes reduced LVDP to a lower extent in females than in males, and the diabetes-induced depressions in both +dP/dt and -dP/dt were lesser in females than in males. Diabetes elicited a lesser reduction in the amplitude of [Ca²⁺]_i transients in females compared to males, a lesser reduction in SR-Ca²⁺ load and less increase in basal [Ca²⁺]_i. Similarly, the elementary Ca²⁺ events and their control proteins were clearly different in both sexes and these differences were more marked in diabetes. Diabetes-induced depression of the Ca²⁺ sparks amplitude was significantly less in females than in matched males. Levels of cardiac ryanodine receptors (RyR2) and FK506-binding protein 12.6 (FKBP12.6) in control females were significantly higher than male ones. Diabetes induced less RyR2 phosphorylation and FKBP12.6 unbinding in females. Moreover, total and free SH groups were significantly less reduced, and PKC levels were less increased, in female than in male during diabetes. The present data related to local Ca²⁺ release and its related proteins describe some of the mechanisms that may underlie sex-related differences accounting for female to developing less frequent cardiac diseases.