The International Conference on Operational Research (KOI) is the major event organized by the Croatian Operational Research Society (CRORS) since 1991. In the period from 1991-1996. it was organized every year, while from the 1996. to today, it is organized every two years. The objective of the KOI conference is to bring together researchers and practitioners from various aspects of operational research for introducing new OR achievements. Main intention of the conference is to exchange ideas and experiences from direct contacts with researches of common interest, particularly including young researches in scientific work. Our mission is to promote Operations Research as an academic discipline and a profession. 14 conferences KOI were successfully held so far in different cities of Croatia settled at the beautiful Adriatic seaside or in the continental part of Croatia, such as: Rovinj, Trogir, Pula, Split, and Zagreb. The next 14th Internationa Conference KOI 2014 is to be organized in Osijek, a small but charming university city in the northern part of Croatia.