We were studied H2S-dependent calcium accumulation in cardiac mitochondria in condition when cyclosporine A-sensitive mitochondrial permeability transition pore (MPTP) was not inhibited. An active Ca2+ accumulation in organelles occurs if it was used calcium in concentration of 5.10-5 and 10-4 mol/l, as evidenced by the increase of Fluo-4 AM fluorescence by 46 %. It is established that hydrogen sulfide donor NaHS showed inhibitory effect at high concentrations (10-4 mol/l) and activating effect at low (10-7 mol/l) concentrations on the calcium accumulation process. It was shown that mitochondrial origin H2S also influences the mitochondrial ability to accumulate calcium and probably increases their calcium capacity. Thus, inhibition of H2S synthesis enzyme 3-merkaptopiruvatsulfurtransferase by it inhibitor O-carboxymethylhidroxylamine (O-CMH, 10-3 mol/l) significantly reduced the rate of fluorescence. However, H2S, which is synthesized in organelles, inhibited the formation of calcium induced MP. Thus, the increase of H2S-dependent Ca2+ accumulation does not causes induction of MPTP and likely leads to increase of mitochondrial calcium capacity and, consequently, to the reduction of this cation in the cytoplasm, which can be regarded as one of the mechanisms for cardioprotection.