The high accuracy of sex assessment (88.3 percent) in the pooled sample suggests that discriminant analysis of the noted sacral base traits is a valid method of estimating the sex of skeletal remains from a range of populations. Of the four variables of the sacral base measured, only the three related to the first sacral vertebra (S1) showed high sex discrimination potential. These three variables are the area, perimeter, and the maximum transverse diameter (m.t.d.). The m.t.d. is the distance between the two most laterally projecting points on the body of S1 measured perpendicular to the midsagittal plane. The maximum superior breadth (m.s.b.) of the sacrum was not very useful for sex prediction. The m.s.b. is the maximum transverse distance between the most lateral parts of the sacral base measured perpendicular to the midsagittal plane. A discriminant function analysis of the three variables of S1 produced a prediction accuracy of 92.1 percent for the Bolognese sample and 84.2 percent for the Sassarese sample. The study demonstrated the utility of image processing in sex-determination studies, as it enabled precise, quantitative measurements of sexually dimorphic bone traits (e.g., the area and perimeter of S1). The study used 114 sacra of known sex and age from 2 early-20th-century Italian populations, 1 from Bologna, northern Italy (n=76) and the other from Sassari, Sardinia (n=38). 10 tables, 3 figures, and 24 references