This paper examines the question of whether the costs of ambulatory medical care (AMCC) in a universal health care system, such as that in Quebec, are related to household income. Questionnaires completed by 32,000 respondents for the Enquête Santé-Québec, 1987 (ESQ87) were matched with records in the Quebec Medicare system (La Régie d'Assurance-maladie du Québec, RAMQ). Approximately 90 per cent of the individuals were matched. Respondents living in remote regions were excluded from the study since a major portion of medical care in these regions is not reimbursed through fee for service; visits to physicians not on fee for service are not recorded in RAMQ files. At the individual level, the costs of ambulatory medical care over a two-year period decreased slightly with income, but at the household level, costs increased for those with higher incomes since the number of individuals in the households increased with income. These associations disappeared when the age of the respondents was taken into account. State of health is directly related to costs of care. Among health risks, availability of social support decreases costs of AMCC for both children and adults, while unemployment increases costs for adults only. Education of parents is linked with higher levels of costs for children, but AMCC decreases with increased education of adults. Finally, costs are lower for children in larger families compared with those in smaller families. To conclude, income does not affect costs of AMCC in Quebec, although variables associated with income, such as education, unemployment and family size, do have definite effects on costs. The absence of a link between psychological distress and costs for the elderly is a matter of concern since it confirms the difficulty the elderly experience in accessing psychiatric care.