A total of 2,515 individuals attending a large military hospital in Saudi Arabia who had appropriate radiologic evidence of treponematosis were studied clinically and serologically. The indications are that nonvenereal treponematosis (bejel) exists in considerable numbers among the nomadic communities living in rural areas. In contrast, venereal syphilis is less common in this population and is found almost exclusively in urban populations. Some of the high-risk regions for bejel have been identified. Many individuals from nomadic communities complained of persistent pain in the lower limbs, which was often associated with radiologic evidence of osteoperiostitis of the long bones. It also appears that within the last 30 years bejel has become clinically attenuated, with the majority of seropositive individuals having latent disease. A hypothesis is put forward that persistent lesions are sustained by superinfection and that improvements in hygiene have resulted in a decrease in the incidence of reexposure. Measures to control the infection are outlined.