The neuroprotective effect of betaine, one of the components of Lycii Fructus, on glutamate-induced neurotoxicity in primary cultured chicken brain cells were examined. Betaine was found to attenuate glutamate-induced neurotoxicity at the concentration of $5{sim}10{;}mM$ in both morphological and chemical aspects. The pretreatment of chicken brain cells with $5{sim}10{;}mM$betaine for 2hr at the 12 th day of culture before the 40min-exposure to $500;{mu}M$ glutamate significantly increased the survival rate of nerve cells in chicken brain. Betaine could also raise the decreased LDH-level in chicken brain cells which were induced neurotoxicity with $100;{mu}M$ glutamate. LDH value was decreased to 63% of control level in chicken brain cells at the time of 48 hr after the exposure to glutamate. However, the pretreatment of chicken brain cells with 5 mM betaine for 2 hr before the exposure to glutamate prevent the decrease of LDH in cells showing 90% of control level. Nevertheless, the remarkable neuroprotective effect of betaine on the glutamate-induced neurotoxicity in cultured chicken brain cells could not be observed when betaine was simultaneously administrated with glutamate.