The paper presents the results of archaeological research on animal remains found in the territory of Chornobyl hillfort and its surroundings. The Medieval Chornobyl was an important settlement of the sparsely populated Kyivan Polesia, a vast land of peat bogs and boreal forests. Today, the city is the centre of Chornobyl Exclusion Zone that was established after the 1986 nuclear disaster. Archaeological surveys have been conducted in this restricted area since 2003 and a significant amount of materials has been amassed during excavations of Chornobyl hillfort. In this paper, we analyse 1060 specimens of fish, birds and small mammal remains in order to reconstruct the economy of the Chornobyl hillfort and the environmental conditions of the surrounding area. The obtained result allow to suggest that (1) fishing and hunting played a considerably higher role in life of the settlement as opposed to animal husbandry, (2) the latter was insignificant because of the surrounding environmental conditions, in particular due to the predominating areas of wetlands and forests, and the small portion of arable lands. When comparing the current species composition of the Chornobyl area with the list of identified medieval remains, we can notice that species dynamics have been affected by both natural (warming, shifts of natural zones) and anthropogenic (fishing, hunting, deforestation disturbance, wetland drainage) factors. In general, our results suggest that the Medieval Chornobyl was surrounded by a typical boreal faunal assemblage with a predominance of water-related (waterfowl and semi-aquatic) species among its terrestrial component.