We describe the patterns of cancer incidence for common cancers in Gulf Cooperation Council countries during 1998-2001. A total of 32 291 cases of cancer were diagnosed (16 342 in males; 15 949 in females). Male preponderance was observed only in Saudi Arabia and Oman. The age-standardized incidence of all malignancies per 100 000 in both sexes was highest in Qatar followed by Bahrain, Kuwait, Oman, UAE and Saudi Arabia. Paediatric cancer ranged from 9.5% of total cancers in Saudi Arabia and UAE to 4.0% in Bahrain. In all countries, the mean age at diagnosis was higher in males than females; cancer of the lung and prostate were commonest among males, and cancer of breast and thyroid among females. Lung cancer ranked second among Bahraini women.