A technical herbicide containing isopropyl amine salt of glyphosate was tested for induction of chromosome aberrations (CA) and sister chromatid exchanges (SCE) in cultured bovine peripheral lymphocytes. Cultures were exposed to a glyphosate formulation at concentrations ranging from 28 to 1120 micromol/l without and with metabolic activation. No clastogenic effect of the herbicide was found. Its genotoxic effect was confirmed in the SCE assay after 24 h of incubation. A statistically significant elevation in SCE induction was observed in each of the donors after application of the product at doses ranging from 56 to 1120 micromol/l. The highest concentrations (560 and 1120 micromol/l) also caused reduction of mitotic and proliferation indices. In the 2 h-assay with metabolic activation a statistically significant frequency of SCE was observed only in cultures treated with the agent at a concentration of 140 micromol/l.