Abstract: AIM To evaluate the effects of diabetes on the expressions of Ca2+ channels and regulatory proteins on sarcoplasmic reticulum (SR) in rat cardiomyocytes. METHODS Sprague Dawley rats were divided into four groups (n=6, each group): group A (control group) and streptozotocin-induced diabetic groups: group B (4-week group), group C (8-week group), and group D (12-week group). Expressions of Ca2+ channels and their regulatory proteins were assessed by RT-PCR (mRNA) and Western blotting (proteins), respectively. RESULTS With the progression of diabetes, expressions of both ryanodine receptor 2 (RyR2) and sarcoplasmic reticulum Ca2+-2ATPase (Serca) decreased significantly, with the downregulation of FKBP12.6 and upregulation of phospholamban. CONCLUSION With progression of disease, diabetes induces the declines in expressions of Ca2+-associated channels and regulatory proteins on SR in cardiomyocytes of rats, gradually and significantly.