He retired from active scientific work in 1905, dividing his time between his private estate and Switzerland. In 1922, he accepted an invitation to head the division of agricultural bacteriology at the Pasteur Institute at an experimental station at Brie-Comte-Robert, France, about 30 km from Paris. During this period, he worked on a number of topics, among them iron bacteria, nitrifying bacteria, nitrogen fixation by "Azotobacter", cellulose-decomposing bacteria, and culture methods for soil microorganisms. Winogradsky retired from active life in 1940 and died in Brie-Comte-Robert in 1953.