The aim of this study was to investigate the genotoxic risk to workers occupationally exposed to coal combustion products in Afsin-Elbistan A power plant, located in south-eastern Turkey. We analysed chromosomal aberrations (CAs), polyploidy, sister-chromatid exchanges (SCEs), and micronuclei (MN) in 48 male workers without a history of smoking, tobacco chewing, or alcohol consumption. The results were compared with a control group of 30 healthy male individuals without exposure to any known genotoxic agents. The mean frequencies of CA, polyploidy, SCEs (P < 0.01), and MN (P < 0.05) were significantly higher in workers than in the control group, by the Mann-Whitney U-test. Spearman's rho correlation analysis revealed a significant increase in the frequency of CA and MN with increasing years of exposure (P < 0.05). However, there was no significant effect of age on the cytogenetic markers analysed in both groups (P > 0.05). The data obtained from this study clearly showed chromosomal hazard in the peripheral lymphocytes of workers exposed to coal combustion products in Afsin-Elbistan A power plant for several years. This cytogenetic damage might be attributed to the cumulative effects of several substances due to chemical complexity of the coal ash and gaseous emissions rather than a specific substance. © 2006 Elsevier B.V. All rights reserved.