LUCENA DOS SANTOS, E. R. S.; ALBUQUERQUE, P. P. F.; ALBUQUERQUE, P. V.; OLIVEIRA, B. D. R.; CAIAFFO, V. Determination of sex based on the morphometric evaluation of the proximal tibia. Int. J. Morphol., 36(1):104-108, 2018. SUMMARY: Anatomic differences are found between human males and females. These characteristics of sexual dimorphism vary across populations and have important implications for the study of human evolution. Researchers have employed anthropological tools for the characterization of human cadavers in different states of decomposition using complete skeletons, isolated bones or even bone fragments. The aim of the present study was to differentiate males and females based on morphometric aspects of human tibias from the Brazilian population. Sixty pairs of adult human tibias were obtained from bone collection of the Anatomy Sector of the Department of Animal Morphology and Physiology of the Rural Federal University of Pernambuco, Brazil. Ten measurements were made on the joint face of the tibial plateau: Anteroposterior diameter of the joint surface of the medial condyle (APM), Transverse diameter of the joint surface of the medial condyle (TM), Anteroposterior diameter of the joint surface of the lateral condyle (APL), Transverse diameter of the joint surface of the lateral condyle (TL), Anterior transverse measure of inter-condyle area (ATI), Posterior transverse measure of inter-condyle area (PTI), Middle transverse measure of inter-condyle area (MTI), Anteroposterior measure of inter-condyle area (API), Anterior measure of intercondyle area (AI) and Posterior measure of inter-condyle area (PI). The median morphometric values for the males' proximal tibia were: APM -4.707 ± 0.406; TM -3.024 ± 0.307; APL -4.023 ± 0.414; TL -3.405 ± 0.323; ATI -3.365 ± 0.425; PTIc -1.788 ± 0.307; MTI -1.167 ± 0.279; API -5.140 ± 0.377; AI -2.865 ± 0.249 and PI -2.297 ± 0.344. The median morphometric numbers for the female's proximal tibia were: APM -4.334 ± 0.317; TM -2.702 ± 0.298; APL -3.549 ± 0.382; TL -2.991 ± 0.281; ATI -2.818 ± 0.307; PTI -1.555 ± 0.222; MTI -1.054 ± 0.262; API -4.596 ± 0.303; AI -2.565 ± 0.21; PI -2.031 ± 0.225. All parameters measured showed values significantly higher (p < 0.05) for the male's proximal tibia. The findings demonstrate sexual dimorphism in this leg bone, which can be used with considerable reliability for scientific and forensic purposes. The results of these studies can be useful in cases where other methods are not applicable, increasing the range of options for forensic investigation.