Little is known about the relationships between patient factors and the antihyperglycemic agents that have been prescribed as initial therapy by diabetes specialists for patients with type 2 diabetes. Moreover, there has been little clarification of the subsequent usage patterns and related factors that influenced the continuation or discontinuation of the drug or the addition of another drug. To provide information on these issues, we evaluated the clinical characteristics of Japanese patients with type 2 diabetes for whom different types of oral hypoglycemic agents (i.e., either sulfonylureas, biguanides, or DPP-4 inhibitors (DPP-4Is)) were chosen as initial monotherapy by diabetes specialists and evaluated subsequent usage patterns.Prescription data on 3 different antidiabetic agents from December 2009 to March 2015 from diabetes specialists' patient registries were used to identify variables at baseline related to initial prescriptions; also, the addition of another hypoglycemic drug or discontinuation of the initial therapy was evaluated 1 year after the initial prescription. Analyzed were data on 2666 patients who received initial monotherapy with either a sulfonylurea (305 patients), biguanide (951 patients), or DPP-4I (1410 patients). Patients administered sulfonylureas were older, had a lower body mass index (BMI), longer duration of diabetes, and worse glycemic control than recipients of biguanides. Use of biguanides was related to younger age, short duration of diabetes, and obesity but was negatively associated with poor glycemic control. Older age but neither obesity nor poor glycemic control was associated with DPP-4Is. In all 3 groups a high HbA1c value was related to adding another hypoglycemic agent to the initial therapy. Moreover, adding another drug to a DPP-4I was related to a younger age and higher BMI.Patients' age, duration of diabetes, obesity, and glycemic control at baseline influenced the choice of hypoglycemic agents. Selection of a biguanide differs greatly from that of a sulfonylurea or DPP-4I with regard to age and obesity.