A 65-year-old female presented with symptomatic ascites. Light and electron microscopy examination of omental and peritoneal tissue obtained at exploratory laparotomy revealed amyloidosis. Immunochemical studies of the amyloid tissue showed positive staining with antibodies to transthyretin. Polymerase chain reaction (PCR), single strand conformation polymorphism analysis, and direct DNA sequencing demonstrated a transthyretin phenylalanine to leucine substitution at codon 33. This is only the second reported case of a transthyretin leucine 33 mutation. Moreover, this patient is unique among cases of transthyretin-associated amyloidosis with the clinical presentation of ascites.