35 years have passed since the Chernobyl NPP accident, 10 years – since the «Fukushima-1» NPP accident. At the present time extensive activities on the remediation of the consequences of two major large-scale radiation disasters are performed in the Belorussia, Russian Federation, Ukraine, and Japan. Releases of radiologically significant radionuclides after the Chernobyl NPP accident correspond to 14 exaBecquerel – higher up to an order of magnitude compared to 3 emergence power units of the «Fukushima-1» NPP. The significantly lower release rate and deposition of 80% of the radionuclides released into the atmosphere on the surface of the Pacific Ocean lead to lower up to several orders of magnitude radioactive contamination of the Japanese territory compared to the territories of the former USSR and neighboring countries after the Chernobyl NPP accident. Collective dose to the public due to the Chernobyl NPP accident is higher up to several orders of magnitude compared to the dose to the Japanese population after the «Fukushima-1» accident. No statistically reliable long-term medical consequences are expected for all groups of the Japanese public, additionally exposed due to «Fukushima-1» accident. 134 emergency workers have developed acute radiation sickness due to the Chernobyl NPP accident. Emergency workers with doses higher than 150 mSv had increased radiation-induced morbidity with leukemia and solid cancers. Among the individuals, that were kids or adolescents in the exposure period after the Chernobyl NPP accident and residing on the territories of Belorussia, Ukraine and four most radioactively contaminated regions of the Russian Federation, morbidity with thyroid cancer is increase by a factor of 10 compared to the pre-accidental levels. The following lessons of the Chernobyl NPP and «Fukushima-1» NPP can be derived: faults in the NPP design and lack of response after the recognition of the faults; lack of timely full-scale prophylactic with iodine; unjustified resettlement of the residents of the radioactively contaminated territories several years after the accident.