Insulin-induced allergy is a rare adverse drug reaction since the introduction of recombinant human insulin. However, recombinant insulin-induced allergy is still being reported in 0.1% to 2% of all patients treated with insulin. This allergic reaction varies from mild localized skin reactions to life-threatening anaphylaxis. It has been shown that one-third of insulin allergy cases is related to insulin itself and the remaining occur due to preservatives contained in the insulin preparations, such as protamine, zinc, or metacresol. This case report describes a 75-year-old woman with poorly controlled diabetes who experienced insulin allergy. She complained of urticaria with itching after the injection of insulin. Allergic skin tests showed positive responses to all available human insulin preparations, and specific IgE to human insulin was also detected, which suggested that her urticaria was developed by insulin itself. This is the first case of insulin allergy that was sensitive to all available human insulin preparations and confirmed by the presence of specific IgE to human insulin. It is important to remember that allergic reactions to insulin may be directly associated with adherence and can be the reason of poor glucose control.