Introduction: This study aimed to investigate the relationships between timing of the first physician visit after detection of an abnormal glycated hemoglobin (HbA1c) value at routine annual check and the time to antidiabetic treatment prescription; and understand treatment patterns in patients newly diagnosed with type 2 diabetes mellitus (T2DM). Methods: This retrospective, longitudinal, observational cohort study examined data from JMDC Inc., an administrative claims database. Patients with HbA1c value of at least 6.5% at routine annual check, aged 20 years or older, and prescribed at least one antidiabetic drug were included. This cohort was classified into early physician visit and delayed physician visit groups based on the timing of the first physician visit relative to the median. Patients were monitored from the date of first HbA1c checkup of at least 6.5% to the date of first physician visit with an HbA1c test, and from the date of the first physician visit to the date of prescription of first-line and second-line T2DM treatments. The time to first prescription of antidiabetic treatment for the two groups was then compared. Results: Of 4798 eligible patients, 54.8% were prescribed first-line T2DM therapy less than 2 months from the first physician visit for T2DM diagnosis. A lower percentage of the early group compared with the delayed group required T2DM pharmacological therapy in less than 2 months (46.1% vs. 63.4%). The early group had a longer median time to prescription of first-line therapy [92 days vs. 15 days, p \ 0.0001; hazard ratio (HR) 1.31, 95% confidence interval (CI) 1.24, 1.39] and second-line therapy (1599 days vs. 1315 days, p \ 0.0001; HR 1.22, 95% CI 1.11, 1.34) compared with the delayed group. Conclusion:In Japanese patients with T2DM, early physician visit after abnormal HbA1c detection at routine annual check is associated with a longer period before T2DM medication requirement, and may improve disease course.