ABSTRACT. – The aim of this study was to evaluate the population structure of Callichirus major from a sandy beach in Southeast Brazil and compare the results with previous studies along the Brazilian coast. Some of the evaluated parameters (e.g. population density and size of males and females) differed from other populations established in Brazil. The abundance of individuals varied considerably throughout the sampling period. The dorsal oval length (DO) of males, females, and ovigerous females was 6.55-15.65 mm (10.32 ± 2.25 mm), 5.95-15.05 mm (10.78 ± 2.5 mm), and 10.3-15.0 mm (13.03 ± 1.24 mm), respectively. The bimodal size class distribution of the population may indicate recruitment peaks. There was no significant deviation from the expected 1:1 overall sex ratio throughout the sampling periods and size classes. The average population density was estimated to 0.202 ± 0.494 ind m–2 (0-4 ind m–2). The variations in the evaluated parameters among different populations studied are probably related to differences in environmental and latitudinal conditions and possibly to the influence of human activity in certain localities.