BACKGROUND The aim of this study was to establish a sample group of Turkish population to determine sex from the sternal end of the ribs. Sex determination from the human skeleton bones is a simple and specific method. METHODS The specimens consisted of right fourth (4th) ribs of 78 females and 173 males of known age, sex and race during 1994-1997 in Izmir, Turkey. A discriminant function analysis showed that the most helpful parameter in the young group was superior-inferior height (SIH), and both SIH and anterior-posterior breadth (APB) in the older group. Modified discriminant score formulae for both young and old groups to determine sex for Turkish population was calculated. RESULTS The results indicated that the accuracy of sex determination was 88.6% in the young group (phase 1-4, age 15-32), 86.5% in the older group (phase 5-8, age 33-89). CONCLUSIONS This study indicates that sexual dimorphism can be assessable by using a single rib, right fourth rib in a Turkish population from ages 13 to 89. SIH of the rib is the most reliable parameter; APB follows it.