A laboratory experiment was conducted to determine the phototoxic effect of [Chromium (Cr) Potassium dichromate (K2 Cr2 O7)] on seed germination and seedling growth of cow pea [Vigna unguiculata (L.) Walp.]. The seeds were treated under 5, 25, 50, 75, 100, 125 and 150 ppm of Cr concentration solutions individually. Each treatment was replicated thrice in a randomized block design. Observations were complete on Germination Percentage, Root and Shoot Length, Number of Leaves, Total Leaf Area, Fresh and Dry Weights of seedling. And Phytotoxicity, Tolerance Index, Vigour Index and pigments content such as Chlorophyll ‘a’, Chlorophyll ‘b’, Total Chlorophyll and carotenoid content of cow pea seedlings at 14th days of seedlings. Among the results gradual increase in Cr concentration under different treatments significantly leads to inhibition of seed germination and other growth parameters. Percentage of phytotoxicity showed an increasing trend with gradual increase in Cr concentration for the cow pea seedlings. Maximum inhibition in all growth parameters and pigments content were recorded.