The pancreas is about the size and shape of the hand; the tail points to the spleen, and the head is nestled in a loop of the duodenum. Loss of the exocrine (digestive) functions commonly leads to severe gastrointestinal disturbances, malabsorption, a cata­ bolic state, and weight loss in the face of an adequate diet. Loss of endocrine pancreatic function leads to a large spectrum of disorders associated with the loss of hormone secretions; the most common and most severe is diabetes mellitus. Loss of the entire pancreas owing to trauma, surgery, atherosclerosis, or other medical problems leaves the patient in a digestive and metabolic crisis. The correct diagnosis of pancreatic disorders remains a challenge given the multi­ faceted function of the pancreas. The clinical laboratory plays an important role, and other tools such as CAT scans, ultrasound, radiographs, biopsies, and even surgery are used to make a diagnosis. The emphasis of Clinical Pathology of Pancreatic Disorders is on the clinical laboratory definition of pancreatic pathology. Disorders of the endocrine pancreas can be highly complex, and sophisticated tests are needed to determine the nature of the disease, its prognosis, and its optimal treatment. Diabetes is the most common of the endocrine diseases; it presents in many ways, and has varied etiologies. We now know that the diabetes of childhood is usually an autoimmune disease, and this has a major effect on the treatment of these individuals.