Allergy to insulin became a rare complication due to the introduction of recombinant human insulin preparations. Nevertheless, allergic reactions to components of such preparations can occur. We report a case of a 61-year-old man with an atopic background and affected by diabetes mellitus type 2 since 27 years, who experienced generalized allergy to insulin at the moment of switching oral anti-diabetics to insulin. Prick tests revealed an allergy specifically to zinc, and the patient was treated with zinc-free glulisine insulin. After 8 months of such treatment, patient's glucose is stable and he never experienced allergic reactions to insulin injections. Even insulin allergy due specifically to zinc is rare, such complication must be assessed especially in a patient suffering from multiple allergies.