Pancreatic exocrine insufficiency (PEI) is one of the long-term consequences of chronic pancreatitis (CP). Majority of patients with PEI were undiagnosed or undertreated. Inadequately treated or subclinical severe PEI causes malnutrition and may pose the patients at risk of premature atherosclerosis and cardiovascular events. Indication of pancreatic enzyme replacement therapy (PERT) is patients with severe PEI, as indicated by the presence of steatorrhea, diarrhea, weight loss, fecal fat > 7 g/day, (13) C-mixed triglyceride breath test < 29%, fecal elastase < 100 ug/g stool, imaging or endoscopic findings of pancreatic ductal dilatation or calculi, and eight endosonographic criteria of CP. The mainstay treatment of PEI is PERT. Dietary fat restriction is unnecessary. PERT with lipase > 40,000 U per meal is recommended. Enteric-coating may be preferred to conventional enzymes because of the availability of high-dose preparations and no need of acid suppression co-therapy. Administration of enzymes with meals is proven to be the most effective regimen. Response to PERT should be measured by the improvement of patients' symptoms, nutritional status, and, in selected cases, by fecal fat or (13) C-mixed triglyceride breath test. Patients unresponsive to PERT should be checked for compliance, increase the dose of lipase to 90,000 units/meal or co-therapy with proton pump inhibitor. In patient with previous gastrointestinal surgery that may interfere enzyme-food mixing, opening the capsules and administering the enzyme granules with meals. Finally, search for small intestinal bacterial overgrowth syndrome and other causes of small bowel malabsorption.