Several in-depth studies have shown that the sternal extremity of the fourth rib can be used in estimating age as well as in determining sex, as illustrated in North American whites and blacks. Yet biological differences between populations may preclude the cross-application of standards. To test this hypothesis and develop a sex determination standard for the Turkish population, a sample of the sternal ends of the fourth rib was collected from 294 individuals autopsied in Istanbul. Dimensions from the superior edge to the inferior one (SI) and the anterior edge to its posterior edge (AP) were measured with a caliper. SI height proved to be the most dimorphic dimension and both dimensions together could give an accuracy of 86 percent to 90 percent. It should be noted that population and age specificity are essential in determining sex from the rib. Yet its accuracy is as good as, if not better than, many bones of the postcranial skeleton. Tables, references