Professor Leszek Kuźnicki, an outstanding protozoologist, the President of the Polish Academy of Sciences in the years 1993–1998, died in Warsaw on February 3, 2023 at the age of 94. Throughout his professional life, he was associated with the Nencki Institute of Experimental Biology. Moreover, he chaired the Cytobiology Committee as well as the Evolutionary and Theoretical Biology Committee of Polish Academy of Sciences. He played a significant role in creating the modern scientific infrastructure in Poland. Throughout the years of his activity, he strongly advocated the idea of maintaining high standards of excellence in research work. He used to say that education should be available to everyone without exception, while scientific work is only intended for the most motivated and the best. It is with deep regret that we say goodbye to a man dedicated entirely to science and the Polish Academy of Sciences.