Objectives To evaluate the clinical results of insulin degludec/aspart (IDEgAsp) therapy and its effect on the fear of hypoglycemia. Methods A prospective observational study has been conducted through surveys of 36 patients using insulin because of type 2 diabetes mellitus who initiated treatment with IDegAsp switching from other insulins. Patients, 18–75 years old, were recruited to the study, consecutively. Participants’ age, gender, height, weight, body mass index (BMI), daily insulin dose, glycated hemoglobin (HbA 1c ), hypoglycemia rate, hypoglycemia fear survey (HFS) were recorded at the beginning of the study. By the end of 12th month, data was re-measured and compared with each other. Results HbA 1c was declined by mean of −1.59% (95% CI −1.06 to −2.12, p<0.001). There was also a significant decrease in mean, daily insulin dose, weight and BMI values of patients via IDegAsp. While there was an increase in the amount of dipeptidyl peptidase 4-inhibitors (DPP4-i) and sodium-glucose co-transporter 2-inhibitors (SGLT2-i), there was a decrease in daily injection frequency. There was also a significant decrease in the median values of monthly hypoglycemia rate (from 2.0 to 1.0, p<0.001) and the entire HFS scores (HFS-T: from 1.09 to 0.73, p<0.001; HFS-B: from 0.83 to 0.60, p<0.001; HFS-W: from 1.33 to 0.88, p<0.001). There was a strong positive correlation between ΔHFS-B and daily injection frequency (Rho: 0.398; P: 0.016). Conclusions IDegAsp co-formulation, combined with DPP4-i and/or SGLT2-i, can provide usefulness in terms of rates of hypoglycemia, reduced HbA 1c , less injection administration, and decreased the fear of hypoglycemia in diabetics.