Nickel (Ni) is an indispensable micronutrient for plants. At higher concentration Ni becomes toxic for various plant species. Black gram (Vigna mungo L.) seed was grown on different concentration of Ni to study its toxic effect on seedling growth and biochemical parameters. The objective of this study was to investigate the effect of nickel on photosynthetic pigment, protein and sugar content and catalase activity in black gram leaves. One day old seedlings of black gram were subjected to different concentrations of nickel sulphate (0.01, 0.5, 5 and 50 ppm) every alternate day with nutrient solution. Plants were harvested after 15th days for determined photosynthetic pigment, protein and sugar content and enzymes activities. In growth parameters i.e. radical and plumule length, fresh weight and dry weights were also found to increase with further decrease in concentration of Ni up to 5 ppm in crop. The tolerance in Vigna mungo with respect to physiological attributes (chlorophyll a, b and total; protein and sugar content; catalase activity) were increased with decrease in concentration of Ni upto 5 ppm, whereas, these parameters were increase with further decrease in Ni concentration (50 ppm).