Type 1 diabetes mellitus is characterized by absolute insulin deficiency, which requires life‐long insulin replacement. Exogenous multiple‐daily insulin injections are most commonly prescribed for patients with type 1 diabetes mellitus. However, exogenous insulin supply often fails to cope with real‐time changing life‐log variables, such as activity, diet and stress, which results in recurrent hypo‐ and hyperglycemia in patients with type 1 diabetes mellitus. Islet transplantation is an ideal method to treat patients with type 1 diabetes mellitus, as it can restore the endogenous capacity of glucose‐stimulated insulin secretion. However, due to donor scarcity and technical barriers, only a limited number of islet transplantations have been carried out in Asia, including South Korea. Since 2013, our center has carried out two allogenic islet transplantations, with one case leading to near total insulin independence after one‐to‐one islet transplantation. Although the other patient failed to restore endogenous insulin production, there was a remarkable improvement in hypoglycemia. We speculate that islet transplantation remains an important and ideal treatment option for patients with type 1 diabetes mellitus who suffer from recurrent severe hypoglycemia.