The aim of this thesis was to describe the term reasonable time, its development over the years and the current phase in which the parties' right to realize the content of this institute is guaranteed to hem by the Constitution of the Republic of Croatia, other relevant national laws and the Convention for the Protection of Human Rights and Fundamental Freedoms. The question of its complexity has been and will be a stumbling rock for many legislators and judical systems, because it's very origin in the Republic of Croatia was like that. From the very beginnings and the first Croatian Constitution, which did not recognize this institute, to the latest proposals on changes to the law on civil procedure, where the rights to a trial within a reasonable time is realized in the widest scope so far. Although perhaps too slow, the effort being made to improve the entire system and adapt it to the needs of people who need this protection is on the rise. The situation in Croatia is rapidly improving and the key obligation of the competent legislators is to continue on this path and continue to enact regulations that will further rationalize the organization of the judiciary.