OBJECTIVES: Although Canada is reputed to be an international leader in diabetes surveillance, there are gaps in knowledge about effectiveness of management, resource utilization and health outcomes of people being treated for diabetes.  The objectives of this study were to follow a cohort of newly diagnosed persons with diabetes in South-Western Ontario (SWO) over a 5-year period to document epidemiology, management, baseline characteristics, clinical outcomes and resource utilization.  METHODS: Data from this cohort were compared to an age and gender matched control group of individuals without diabetes.  Regression analyses were conducted to evaluate the impact of anti-diabetic medications on glycemic levels and control after adjustment for age, gender and baseline HbA1c. RESULTS: A total of 3861 individuals with newly diagnosed diabetes in 2002 were identified.  The mean HbA1c levels increased from 7.4% at time of diagnosis to 8.21% at the end of the study in 2008. A similar trend was observed for fasting glucose levels (6.71% at baseline to 7.41% in 2008). After controlling for covariates, regression analysis results indicates that continuous and intermittent  use of anti-diabetic drugs compared to no drug use had no significant impact on 2-year HbA1c levels.  Further, the results of our study indicate that a large proportion of the cases had uncontrolled hypertension and hyperlipidemia.  An interesting finding is that the average number of physician visits decreased from 7.9 per year at baseline to 4.8 at the end of 5 years in cases, whereas in controls, physician visits increased from an average of 6.8 at baseline to 7.4 five years later. Hospitalizations decreased over time from an average of 6 days at baseline, to 2.4 days at the end of 5 years.  CONCLUSIONS: Consistent with other studies, these findings suggest that a minority of people with diabetes in South-Western Ontario achieved optimal glycemic control.