Since the introduction of insulin there have been a number of case reports dealing with insulin resistance. Martin1 and many authors have arbitrarily selected the requirement of 200 units of insulin a day as the demarcation between the insulin-sensitive and the insulin-resistant diabetic patient. Smelo,2 in a thorough and critical review of the problem of insulin resistance, presented 54 cases that had been reported in the literature up to 1948. Twelve of these insulin-resistant patients exhibited a local or general allergic response to insulin.3 Kyle and Dyer4 have recently encountered such a patient, and we wish to describe another patient with insulin resistance associated with local and systemic allergy to insulin. REPORT OF CASE Mrs. B. S.,5 a 23 year old woman, was admitted to the Hospital of the University of Pennsylvania on Dec. 19, 1949. She had been in her usual state of good