AbstractThe purpose of this study was to validate the technique developed by Paiva and Segre for sex identification using the mastoid process. Total mastoid area is calculated by adding the right and left triangular areas defined by three distinct craniometric points: the Asterion, Porion and the Mastoidale. Eight skulls (40 males and 40 females) were analysed and total area calculated using Heron's formula. The mean total area of the male skulls is higher compared to females (1461.06 mm2 vs 1222.79 mm2). Independent t-tests reveal that there are significant differences between males and females, with p-values less than 0.0001.