Aim To investigate the role of calcium in tumor necrosis factor α（TNF-α）-induced cardiomyocyte hypertrophy. Methods The protein content was assayed with Lowry’s method . The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with ［³H］-leucine incorporation method. ［Ca²⁺］i transient was measured by Till image system by cell-loading Fura-2/AM. Results 2-APB, a selective IP₃R inhibitor, and/or ryanodine, a selective RyR inhibitor, significantly suppress the elevation of the amplitude and the rates of the spontaneous Ca²⁺ transients induced by TNF-α in cultured ventricular myocytes from the neonatal rat. Nifedipine, an L-type calcium channels antagonist, had little effect on it. The increase of protein content, ³H-leucine incorporation and cell size induced by TNF-α were significantly suppressed by 2-APB, and/or ryanodine. Nifedipine had no effect on it. Conclusion TNF-α induced cardiac hypertrophy through increasing of intracellular Ca²⁺ in cultured ventricular myocytes from the neonatal rat. It was induced by both IP₃R and RyR, not by L-type calcium channels.