Based on the private archive sources, published sources and literature and periodicals, author analyzes the war chronicle of the 83rd independent Zagreb battalionAlso, the paper will try to explain the formation of 83rd independant war batallion of Zagreb which happened on 23rd of December 1991. but it will be written about repeal of a same batallion on 31st of July 1992. The most of the graduate thesis relates to the situation in the East Slavonian battlefield before and after the arrival of military volunteers from Zagreb, as well as other battles in the Republic of Croatia and Bosnia and Herzegovina where this military unit participated. The main goal of forming, 83rd Independent Zagreb Battalion was to help and unblock Vukovar, but after an unsuccessful attack on Marinci, independent Zagreb companies were deployed on the line of defense of Vinkovci. In the period of successful hostile assault actions from mid November to early December 1991, independent Zagreb companies will take part in defensive operations and thereby contribute to stopping further hostilities in the territory under the control of the Croatian forces. After the signing of the Sarajevo treaty and stabilization on the battlefield Vinkovci, the 83rd Independent Zagreb Battalion participated in other battlefields. It is also important to point out the contribution of foreign military volunteers, who made a significant number of members of the unit.