Abstract: The precision of age determinations of C. auratus between two readers and the use of scale and otolith(lapillus)from 175 and 168 individual fish collected in the Honghu Lake and the Dongting Lake, respectively, were compared. Ages assigned to scales and otoliths by the two independent readers agreed 50.9% and 92.6% for samples from the Honghu Lake and 90.5% and 97.0% for those from Dongting Lake of the same time, respectively. Age agreement between scales and otoliths was low(56.6% and 41.7% for reader 1 and reader 2, respectively)in the Honghu Lake population and high(91.7% and 82.1% for reader 1 and reader 2, respectively)in the Dongting Lake population. Generally, more annuli were detected on otoliths than on scales as fish age exceeded 4 years, and the maximum ages identified were 8 years from otoliths, 6 from scales in the Honghu Lake population. It is demonstrated that scale is only useful for estimating age of the C. auratus population with few age groups and rapid growth, and otolith is a better structure than scale to use for estimating age of C. auratus, especially for the population with slow growth and more age groups like that from the Honghu Lake.