Children of subcontinental (Indian and Pakistani) origin living in the United Arab Emirates (UAE) have previously been shown to have a higher relative frequency of ALL when compared to other ethnic groups. To analyze the possible effect of social class in this difference, a study of socioeconomic factors was conducted through personal interviews with the families of 115 children with lymphoid malignancies. The patients belonged to three ethnic groups: (1) UAE; (2) other Arabs; and (3) Indian subcontinent. UAE parents had the highest income and number of rooms in their house, but the lowest level of education. Occupational categories were significantly different for the three ethnic groups. While 41% of the UAE fathers worked in the army or the police, the majority of Arab and subcontinental fathers worked as government adminstrators or professionals. UAE families had the highest number of children in the family, subcontinental families the lowest. The number of children per family was inversely related to the parents' education level. Multiple regression analysis showed parental education level and house size to be significantly associated with ethnicity, while parental consanguinity was significantly associated with the diagnosis of lymphoma. It is difficult to define social class in the UAE population. While income and property ownership would place the UAE nationals in the highest category and the subcontinental group in the lowest, education level and occupational category would place the Arab and subcontinental groups higher. The smaller family size and higher education level in subcontinental families corresponds to the previously found higher relative frequency of ALL in this ethnic group and could lend support to the possible infectious etiology of the disease.