In a study of 200 fresh adult cadavers, calvarial thickness was measured at selected points. The variables of age, height, weight, sex, and race were subjected to multiple regression analysis to determine which were significant in the determination of skull thickness. The results indicate that weight, race, and sex are the most important variables. However, the magnitude of the effects of these variables is minimal when considered in relation to clinical requirements. The study provides the clinician with a reasonable basis to obtain preoperative estimation of the thickness of calvarial grafts in the adult at four commonly utilized points.