Diabetes is the most common cause of peripheral neuropathy, and painful diabetic neuropathy (PDN) affects approximately 30% of diabetic patients with neuropathy. It is extremely distressing for the patient and poses significant management difficulties because no treatment provides total relief, and side effects of therapy are a major limiting factor for titrating therapy. Understanding the pathogenesis of diabetic neuropathy may lead to the development of new treatments to prevent nerve damage, and a better understanding of the mechanisms that modulate pain may lead to more effective relief of painful symptoms. We provide an update on the pathogenesis, diagnosis, and treatment of PDN.