We report a case of acute, painful polyneuropathy in a woman with newly diagnosed type I diabetes mellitus associated with a precipitous drop in hemoglobin A1c . She has had poorly controlled diabetes mellitus type I for 5 years despite diet, execise, oral therapy because she has been diagnosed type II diabetes mellitus 5 years before. She experienced diabetes ketoacidosis, and she presented with a hemoglobin A1c of 17.8% and was hospitalized for continuous subcutaneous insulin infusion. Following the initiation of continuous subcutaneous insulin infusion, the patient's hemoglobin A1c fell to 6.1% within 2 months. During this 2-month period, she developed severe burning in her hand, feet and trunk, accompanied by tingling paresthesia and dysesthesia. Nerve conduction studies were consistent with mild sensorymotor peripheral neuropathy. Initially, she required opiate analgesics for pain control because gabapetin or tramadol/acetminophen did not help. Three months after presentation, the patient showed dramatic improvement and her pain resolved. Although not well described in the neurologic literature, this case represents insulin neuritis, one of the few diabetic neuropathies that has a favorable outcome.