The legacy of N.V. Timofeev-Ressovsky is a multifaceted phenomenon comprising numerous evolutionary problems. The long-term interest of Timofeev-Ressovsky in the effect of the radiation on the heredity probably had drown his attention to a more profound and extensive problem of microevolutionary processes, which in contrast to macroevolution may be not only clearly detected but even viewed literally “in the real time” mode. One can only regret that Timofeev-Ressovsky didn’t live long enough to see how his own predictions brightly reflected in the modern evolutionary symbiogenetics. The broadest spectra of evolutionary problems related to symbiosis-including the origin of eukaryotic cell and the permanent coevolutionary “fine-tuning” of symbiotic systems formed by bacteria and plants in the nitrogen-fixing symbiosis give a wealth of experimental data and clearly demonstrate the validity of his predictions. In this short paper we have tried to show the most obvious and bright connections between Timofeev-Ressovsky’s ideas in the area of the microevolutionary processes and current knowledge on the legume-rhizobial symbiosis.