The industrial use of the ionizing radiation (IR) particularly stresses the safe work, regular health control is inevitable. Since previous occupational cohorts reported contradictory data on the incidence of melanoma among nuclear industry workers, and in few publications significant increase of it has been described, our clinic was requested by the industry to screen malignant skin tumours among the workers of a power plant. Within a year we have investigated 556 workers, 275 females and 281 males. Out of them 283, majorly males had been officially confirmed as to be employed at hazardous, but strictly controlled environment for an average of 18 years (1-32 years). To distinguish between IR and environmental UV (UVA+UVB) induced cutaneous malignancies we determined the sun and tanning bed exposure of the workers. One in situ melanoma developed in a woman with type I skin, bullous sunburns in the history, who had worked in safe environment for 26 years. Basal cell carcinoma was identified in two men, each of them worked for more than 20 years with IR (in hazardous environment). One had type I skin, the other had type II skin. These results didn't differ significantly (chi-squared test; p = 0, 2437 and 1, 0) from the national population data and the results of Euromelanoma screening campaign in Hungary. Our data clearly show, that 1./UV exposure and skin type should be evaluated in occupation cohort studies. 2./The melanoma incidence was not significantly higher among the employees of the power plant than in the general Hungarian population, according to the results of our study, the only Hungarian power plant is safe as far as the skin carcinogenesis is concerned.