Observational Study to Evaluate the Efficacy and Safety of Teneligliptin

Inclusion Criteria: 1. The subject is aged ≥19 years 2. The subject has a documented diagnosis of type 2 diabetes mellitus for at least 3 months at the screening visit. 3. Patient who was treated with same dosage of DPP4 inhibitor for at least 12 weeks prior to baseline visit (if patient who has been treated with DPP4 inhibitor and any other antidiabetic drugs, antidiabetic drugs should also have been kept same dosage for at least 12 weeks prior to baseline.) 4. Patient with HbA1c≥7.0% at baseline visit 5. Patient who can be switched to Teneligliptin instead of using DPP-4 inhibitor for glycemic control based on the investigator's judgment 6. Patient (or legal guardian, if applicable) is informed of the full nature and purpose of the study, including possible risks and side effects, and understand this information, voluntarily signed and dated the written informed consent in compliance with protocol before inclusion in the study Exclusion Criteria: 1. Patient with hypersensitivity to the Teneligliptin 2. Patient who treat the Teneligliptin prior to baseline visit 3. A pregnant or lactating female patient