This study compared the data on mandibular fractures that occurred in a city in the United States and one in Turkey between 1991 and 2000. The 210 Turkish patients had 252 mandibular fractures, whereas the 665 US patients had 1042 mandibular fractures. Males accounted for 84% (560 patients) and females for 16% (105 patients) of the cases in the US. The male:female ratio was 5.5:1. In Turkey, males accounted for 76% (160 patients) and females for 24% (50 patients) of cases. The male:female ratio was 3.2:1. Assault (53.7%) was the most common cause of fracture in the US, whereas in Turkey the most common cause was a motor vehicle accident (36.2%). The most common site of mandibular fracture in the US was the angle (27.57%); in Turkey the most common site was the body (28.97%). Many of these variations may be related to socioeconomic, cultural and environmental differences between the two countries.