OBJECTIVE: To explore the correlation between the expression of brain derived neurotrophic factor (BDNF) and presbycusis in the cochleae of the aged rats. METHOD: The mRNA expression of BDNF and presbycusis in the cochleas of the aged rats was quantitated by real time PCR. RESULT: The expression of BDNF in the cochleas of the aged rats with presbycusis was obviously less than that in the control group. And the difference was statistically significant. CONCLUSION: The expression of BDNF is closely correlated to presbycusis in the aged rats.