OBJECTIVES: Unlike older agents, rosiglitazone lowers blood glucose levels by directly acting on insulin resistance, the primary metabolic defect of type 2 diabetes, and has other positive metabolic effects on lipids and blood pressure. Outcomes of patients on rosiglitazone used as combination and monotherapy in routine Canadian clinical practice is reported. METHODS: Five Canadian centers participated in retrospective data collection. Charts were reviewed for over 635 patients on rosiglitazone with the use of a software program designed to track outcomes pre and post Avandia treatment such as glycemic control, metabolic parameters (including renal function, liver enzymes, and lipids) as well as weight, blood pressure and changes in diabetic medications. Patient data were entered into the software and analyzed using standard statistical methodology. RESULTS: In the analysis of 337 patients on rosiglitazone, the average age was 71.6 years with 44% females. Rosiglitazone was started as additional therapy to sulphonylureas (38%) or metformin (42%) or both (33.5%). There were 150 patients on rosiglitazone as monotherapy (44%). The relative reduction in HbA1c was 15.3% at best and 12% at end. Changes in renal function and liver enzymes were not statistically significant. There was a significant improvement in LDL and blood pressure while on rosiglitazone. There were eight patients with elevations of liver enzymes. CONCLUSIONS: In routine Canadian clinical practice, rosiglitazone is effective at lowering both FBG and HbA1c significantly over time and appear to be comparable to, or better than, those reported for the established oral agents. Many patients were able to reach improved targets of HbA1c and FBG with no reported serious adverse events. Further study is required to investigate the beneficial metabolic effects observed on blood pressure and lipids.