The purpose of this study was to describe the patterns of antidiabetic medication use and the cost of testing supplies in Canada using information collected by Saskatchewan's Drug Plan (DP) in 2001. The diabetes cohort (n = 41,630) included individuals who met the National Diabetes Surveillance System (NDSS) case definition. An algorithm was then used to identify subjects as having type 1 or type 2 diabetes. Among those identified as having type 2 diabetes (n = 37,625), 38% did not have records for antidiabetic medication in 2001. One-third of patients with type 2 diabetes received monotherapy. Metformin, alone or in combination with other medications, was the most commonly prescribed antidiabetic medication. Just over one-half of the all patients with diabetes had a DP records for diabetes testing supplies. For individuals (n = 4,005) with type 1 diabetes, 79% had a DP record for supplies, with an average annual cost of 472 +/- 560 dollars. For type 2 diabetes, 50% had records for testing supplies, with an average annual cost of 122 +/- 233 dollars. Those individuals with type 2 diabetes who used insulin had higher testing supply costs than those on oral antidiabetic medication alone (359 vs 131 dollars; p < 0.001).