Superoxide dismutase(SOD) was produced by carrot hairy roots. After increasing in the early exponential growth phase, SOD biosynthesis decreased gs the growth rate of hairy roots declined. High sucrose concentration stimulated the SOD biosynthesis, while inhibiting the growth of hairy roots. Potential inducers were tested for the enhanced production of SOD. The addition of 0.3 mM CuSO4 to the broth showed about 6 fold increase in SOD biosynthesis compared to the results obtained with basic MS medium. Since CuSO4 in the broth inhibited the growth of hairy roots, the addition of CuSO4 to the broth at the late exponential growth phase led to a 12 times higher intracellular level of SOD compared to that in basic MS medium.