The effects of cyclosporine A (CsA) on Angiontensin Ⅱ (Ang Ⅱ )-induced protein contents, c-fos protein levels and cytosolic Ca2+ level ([Ca2+ ]i) in cultured cardiomyocytes of neonatal rats were observed. Total protein contents were determined by Bradford method. The expression of c-fos protein was detected by West blot. [Ca2+ ]i labeled with fluorescent probe Fluo-3/AM was measured under a laser scanning confocal microscope. The results revealed that as compared with control, the total protein contents were increased in cardiomyocytes treated with Ang Ⅱ (10-7 mol/L), which could be inhibited by CsA in a dose-dependent manner. It was found that Ang Ⅱ could increase the c-fos protein expression, which could be inhibited by CsA in a dose-dependent manner.Ang Ⅱ induced the [Ca2+ ]i elevation in cardiomyocytes. CsA did not influence the resting intracellular Ca2+ , but inhibited significantly the Ang Ⅱ-induced [Ca2+ ]i elevation. It was concluded that CsA can suppress the Ang Ⅱ-induced c-fos protein expression and [Ca2+ ]i elevation in single cardiomyocyte, which might play a role in the prevention of Ang Ⅱ -induced cardiomyocyte hypertrophy by CsA.