Mieczysław Łęczycki submitted two designs for the 1928 Olympics, one being the Central Institute for Physical Education in Warsaw-Bielany with his brother Józef, and the design for the Stadium in Warsaw (Szczęśliwice) with Ludwik Oli. Both were awarded first prize in the tender for the stadium. A large stadium with a running track and cycling track was planned to be built in the center of Fort Szcza, which was built around 1880 and abandoned in 1909. However, the plan was dropped, and initial work was stopped in 1928. Like his brother, Mieczysław had a planning office in Łódź, and was president of the Łódź Chamber of Architects in the early 1930s. His architectural designs are clearly assigned to functionalism.