Spontaneous amyloidosis was diagnosed in 11 male and 1 female chimpanzees and confirmed histologically and immunohistochemically. The chimpanzees were ≥15 years of age when first diagnosed and averaged 22.4 years of age. The average survival time after diagnosis of systemic amyloidosis was 1.86 years with a standard deviation of 4.06 years (n=7). The chimpanzees with amyloidosis were asymptomatic except for hepatomegaly, which became more detectable with age. Significant increases in clinical chemistry values, as compared with referenced normals and established normals, of blood urea nitrogen (BUN), asparate aminotransferase (AST), gamma‐glutamyltransferase (GGT), globulin, total protein, creatinine phosphokinase (CPK), sedimentation rate, and triglycerides were found in animals 7 years of age or older with amyloidosis. These serum chemistry values, while increased in chimpanzees with amyloidosis, were generally within normal limits. Immunohistochemistry for both amyloid A protein and amyloid P component‐labeled extracellular amyloid in all chimpanzees with amyloidosis was determined. Amyloid was deposited primarily in the liver. Amyloidosis in the chimpanzee is a chronic, intractable, progressive, fatal disease, and appears to be similar to secondary amyloidosis in other species.