Cyanotoxins, toxic secondary metabolites of cyanobacteria, are able to induce a wide range of negative health effects in the intoxicated organisms. Except for their well-described hepatotoxic or neurotoxic activities, cyanotoxins are also considered to possess other properties, such as immunotoxicity or genotoxicity. The aim of the work was to study the potential cytotoxic/genotoxic impact of selected cyanotoxins (microcystin-LR, cylindrospermopsin and anatoxin-a) on common carp leukocytes. The cells were exposed to the toxins at 0.5 µg/ml for 18 h. DNA damage in the cells was studied with the use of the alkaline version of the comet assay detecting single- and double-strand DNA breaks. Apoptotic cells were identified on the basis of phosphatidylserine translocation in the plasma membrane and the cell viability was checked by the propidium iodide staining. The most substantial changes were detected in the leukocytes exposed to microcystin-LR, in which a high level of DNA damage was observed, but there was also a high number of apoptotic cells. No such effects were observed after cell exposure to anatoxin-a. Cylindrospermopsin did not intensify apoptosis or necrosis, however some increase in DNA damage was detected.