Background: Several meta-analyses compared insulin monotherapy and combined therapy of insulin and oral hypoglycemic agents (OHA). However, these were not consistent and not focused to individualization. Therefore, we try to elucidate the characteristics of patients whose both fasting and postprandial glucose were controlled by once daily basal insulin monotherapy. Methods: The data of this study are part of our previous study which investigated characteristics of responders on different medications for controlling postprandial glucose levels after optimizing fasting glucose levels by insulin glargine. Background OHA cessation for 2 weeks of initial washout period and then insulin glargine was initiated. Oral glucose tolerance tests after initial wash out period and 7 point self-monitoring blood glucose test for 3 days at each step was completed by each subject. Results: The patients in Controlled group were younger, had a lower baseline A1c, and lower OGTT 2hr PPG levels than patients in the Non-Controlled group. Controlled group showed higher homeostasis model analysis % β (HOMA %B), corrected insulin response (CIR) and insulin-to-glucose ratio (IGR) than Non-Controlled group. Homeostasis model analysis insulin resistance (HOMA IR), 1/fasting insulin (by FI) and insulin sensitivity index (ISI) were similar between the two groups. Conclusions: In our study, some patients can be well controlled both fasting and postprandial glucose level with once daily insulin glargine monotherapy. Patients able to do so were younger, had lower baseline HbA1c, lower oral glucose tolerance test (OGTT) 2h PPG and higher makers of insulin secretion.