The numerous ecological catastrophes of the twentieth century caused by humans have found their way into mass culture. Among them is the Chornobyl nuclear accident that took place in Ukraine in 1986. This disaster became a subject of reflection not only in Ukrainian literature but also in world films and computer games. Along with other works on the nuclear theme in world literature, books by Ukrainian writers for children and young adults (YA) such as Leonid Daien's "Chornobyl -- trava girka" ("Chornobyl -- the Bitter Grass") or Yevhen Hutsalo's "Dity Chornobylia" ("Children of Chornobyl") that depict the Chornobyl accident and its consequences for Ukrainians. I explore the Chornobyl catastrophe concept in the above-mentioned books as well as in the cartoon "Travel-book. Ukraine. Ghost Town" and in the game "S.T.A.L.K.E.R." I claim that Ukrainian works on the Chornobyl theme belong to the genre of ecofiction as a warning to humanity about the negative effects of human behavior on the ecosystem, based on ecocritical theory referred to by Buell, Dwyer, and others. My position is that the Chornobyl nuclear theme in children's literature is centered closely on the cultural memory of Ukrainians. In reference to Erll's interpretation of cultural memory as the interplay of present and past in socio-cultural contexts, I consider cultural memory in children's literature as a need to deal with the traumatic experience of the Chornobyl nuclear accident and ethnocide of Ukrainians in their colonial past. My analysis then focuses on the investigation of how these concepts are implemented in children's books, films, and games, via their imagery.