Analysing equity in access to health care in Antioquia, Colombia.Poorer and richer groups' access to health-care was evaluated, as was that of people with insurance and those without it. A Logit model was estimated for analysing the main determinants of access to curative and preventative health-care services; explanatory variables were socioeconomic status, education level, self-reported health status, age, gender, urban/rural location and social security affiliation.There was no difference in health-care service access amongst people affiliated to contribution-based and subsidised regimes. However, financial constraints represented important obstacles for subsidised regime members and those having no affiliation. Contribution-based regime members had greater resources for continuing to receive attention. There was positive bias in using preventative services thereby favouring people having higher socioeconomic status.Educational level, age and being affiliated to social security were the main factors explaining health-care service access. Gender, self-reported health status and geographical location were additional factors explaining preventative health-service access.