Socio-economic status (SES) is recognized as an important factor that influences the utilization of health-care services. We set out to explore this association in the context of hospital admissions for the treatment of ambulatory care sensitive conditions (ACSCs)--chronic conditions normally managed on an outpatient basis. We examined rates of hospital admission for the treatment of ACSCs overall and for three specific conditions: chronic obstructive pulmonary disease (COPD), diabetes and asthma in children. Data were obtained from the Canadian Institute for Health Information, the Institut national de santé du Québec, and Statistics Canada. SES was determined using a measure known as the Deprivation Index, applied at the level of the census dissemination area (DA), the smallest geographical unit for which population statistics are available. This study accounted for 46,173 urban DAs classified into low, average and high SES groups. Statistically significant variations in rates of hospital admission were found across the three SES groups for all four ACSC categories examined. For example, hospital admission rates for COPD and diabetes in the low SES group were about 3.0 and 2.7 times higher, respectively, than those in the high SES group. Further research is needed to understand the mechanisms and underlying causes of higher rates of hospital admission for the treatment of chronic disease among people with low SES.