Several studies have demonstrated that the nuclear power plant accident at Chernobyl in 1986 had a strong impact on the subjective health of the inhabitants in the surrounding regions and that the majority of these health complaints appear to be stress-related. An epidemiological survey among the adult population of the Gomel region in Belarus near Chernobyl showed higher rates of self-reported health problems, psychological distress and medical service use in this region than in a comparable unexposed region. This paper presents an analysis of data on cognitive factors that were collected in this study. The findings support the hypothesis that cognitive variables such as risk perception and sense of control play an important role as mediating factors in the explanation of the observed health differences between the exposed and non-exposed regions. A tentative model is presented to further clarify the role of risk perception in the occurrence of non-specific health complaints after such ecological disasters.