Inclusion Criteria:  1. Had one of the following treatments with alogliptin for the first time as an adjunct to diet and exercise to improve glycemic control:  Monotherapy with alogliptin Combination therapy with the surveillance drug (alogliptin) in case of inadequate glycemic control with metformin or sulfonylurea or thiazolidinedione single therapy Combination therapy with the surveillance drug (alogliptin) in case of inadequate glycemic control with thiazolidinedione and metformin combination therapy Combination therapy with the surveillance drug (alogliptin) in case of inadequate glycemic control with insulin (single therapy or combination with metformin) therapy Combination therapy with metformin in patients who have no prior history of antidiabetic medication and may not achieve adequate glycemic control with monotherapy alogliptin  Exclusion Criteria:  Had alogliptin treatment outside of the locally approved label in Korea Had a contraindication for the use of alogliptin (as described in the Korean product label)