With the goal to study radioadaptation on life-span and observe the role in this phenomenon of genotype, we investigated the dynamics of life-span in 14 consistent generations after chronic gamma-irradiation in heterogenic (Canton-S) and isogenic (Oregon-R spa) Drosophila wild type strains. The gamma-source was 226Ra in dose 60 cGy per generation. The animals kept in standard conditions (25 degrees C and 12 h lighting). Was shown, that the dynamics of median life-span in wild type strains Canton-S and Oregon-R spa was different and the character of alterations depends on genetic heterogeneity. After chronic irradiation in generations in heterogenic line Canton-S since 5 generation cyclic life-span oscillations disappeared, values of median life-span leave on a plateau. Since the 8th generation the life-span values of irradiated populations exceeded all the control values. As a result of the irradiation practically in all generations in isogenic line Oregon-R spa occurs increasing of life-span with the comparing to non-irradiated control. This is possible due to the positive influence of radio-induced heterogeneity on the life-span of isogenic strain. Thus, chronic irradiation led to violation of natural cyclic dynamics of Drosophila life-span in heterogenic strain, discovered in the end 80-s' years by F. Lints and D. Ismaylov. Irradiation of isogenic strain led to increasing of life-span in all generations.