A pot culture experiment was conducted to study the effect of various concentrations of cerium provided as cerium nitrate (0.713, 3.568, 17.841, 89.206 and 446.030 µM) on the growth performance, dry matter production, biochemical constituents and enzymatic activity of cowpea plants [Vigna unguiculata (L.) Walp.]. Low concentrations of cerium were observed to be beneficial for the test plants. A positive correlation was observed between a lower level of cerium (0.713-17.841 µM) and foliar chlorophyll content, relative yield (dry matter) and nitrate reductase activity. Higher levels of cerium (89.206-446.030 µM) significantly increased the proline content and polyphenol oxidase activity of the test plants. Root growth was more adversely affected than shoot growth.