Local or generalized alteration of microcirculation may be expected in diseases of the pancreas. Changes may range from increased permeability of capillaries to hemorrhage. Tissue necrosis may result from prolonged ischemia owing to intravascular coagulation and severely impaired blood flow. It is possible to observe early microvascular changes by intravital microscopy. Klar and coworkers have demonstrated by this method that isovolemic hemodilution improves blood flow under conditions that would otherwise lead to tissue damage. This paper presents the basic microcirculation of the pancreas and the changes that accompany pancreatic disease. It emphasizes that concentration on the changes in microcirculation that accompany the early manifestations of pancreatic diseases, particularly pancreatitis, may reveal important clues to their pathogenesis.