This paper describes the oncological experience on 7,216 patients at two cancer units initiated by one medical team in 1975–1977 at Assaf Harofeh Medical Center in Israel (predominantly serving a Jewish population, 4,671 cases) and at the West Bank Cancer Unit (WBCU), which serves an Arab population (2,545 cases). The two centers have the unique feature of serving two populations residing in close geographic proximity but differing in many cultural and socioeconomic characteristics. Data from the ongoing cancer registries in these two centers are summarized and compare the demographic characteristics of the two study groups, anatomic sites of cancer, methods of diagnosis and extent of disease. The findings at the two centers suggest the presence of different risk factors influencing the site distributions of cancers seen in the two populations served. Among the findings, significantly higher (p < 0.05) estimated relative risks for cancers of the digestive and urinary-genital systems are observed in each sex group at AHMC than at WBCU. Alternatively, the estimated risk of head and neck cancers was significantly higher among both males and females at WBCU compared with their counterparts at AHMC. Differences in risk were also noted for a number of specific anatomic sites of cance