The effect of Ni(2+) on fungal growth, cellular fatty acid profile and lipid peroxidation was studied (with an emphasis on the kinetics of these processes) in the strain of filamentous fungus Curvularia lunata. In the cultures supplemented with 0.2 and 0.6 mM Ni(2+) the lag phase was extended and the specific growth rate decreased, however, the maximum yield of biomass at the stationary phase reached, respectively, 97 and 27% of the control. The treatment with Ni(2+) changed the proportion of 18 C atom fatty acids, with the most significant decrease in the content of linoleic acid (18:2) followed by a rise in the degree of fatty acid saturation. In the mycelia exposed to Ni(2+) the levels of TBARS (lipid peroxidation products) increased and ranged between 156 and 823% over the control. The presented data reveal that the oxidative stress resulting, among others, in membrane lipid peroxidation is involved in the mechanisms of the nickel toxicity towards C. lunata and suggest that this fungus exhibits an ability to cope, to some extent, with the increased level of lipid peroxides.