Ilija Lukačević (1935-2020) was a professor at Faculty of Sciences and Mathematics, at the Department of Mechanics and Astronomy. He was author of several papers, mostly in the field of theory of relativity. Some of these papers and his doctoral dissertation can be found in the Virtual Library of the Faculty of Mathematics in Belgrade, http://elibrary.matf.bg.ac.rs. In this paper we present these works, as well as some details from life of Ilija Lukačević.