A 1. 8-year-old intact female Maltese dog was presented because of a history of chronic diarrhea, polyphagia, weight loss, and coprophagia. The patient was severely emaciated and evacuated very moist and four-smelling, yellow feces. Fecal stain with Sudan III revealed numerous lipid droplets. Result of fat absorption test showed aldigestion. A definite diagnosis was made based on trypsin-like immunoreactivity assay in serum which was low enough to be diagnosed as an exocrine pancreatic insufficiency. After pancreatic enzyme supplement with porcine pancreatin powder, the clinical signs were disappeared. This case report documents clinical manifestations, diagnostic tools, treatment and efficiency of oral pancreatic enzyme replacement therapy of exocrine pancreatic insufficiency in a Maltese dog.