This study investigates the population structure, size frequency distribution and the biometric studies of the rocky snail Thais carinifera in Lake Timsah, Suez Canal. The population was dominated by animals with shell length ranged from 5-5.5 to 5.6-6 cm, which represented 61.96 % of the total individuals. Significant correlations were found between shell length and most of the other parameters (shell width, aperture length, and body whorl), with negative allometric growth. The correlation co-efficient values between shell length and body weight were significant with isometric, positive and negative allometric growth along the study period (July 2006 - September 2007).