From 1956 through 1989, 38 men and 26 women were seen at the Mayo Clinic with biopsy-proven AA. The underlying disorder was rheumatic disease in 42, infectious disease in 11, inflammatory bowel disease in 6, and other causes in 5. All patients were symptomatic at the time of diagnosis. Fifty-eight of the 64 patients had proteinuria or renal insufficiency. Fourteen also had significant symptoms of gastrointestinal amyloid, and 6 had amyloid goiter. None of the patients had symptomatic cardiac involvement, and only 3 had palpable hepatomegaly. Renal, gastric, rectal, fat, and marrow biopsies were positive for amyloid in 100%, 94%, 82%, 58%, and 46% of tested patients, respectively. The median survival of the entire group was 24.5 months. Thirty-five of the 47 deceased patients died as a direct result of their amyloidosis, primarily from complications of renal failure. Nine were successfully treated and had regression of the disease. Two with bronchiectasis responded to long-term cyclic antibiotic therapy, as did 1 patient with osteomyelitis. One patient with inflammatory bowel disease responded to surgical resection, and 1 with familial Mediterranean fever responded to colchicine. Four patients with rheumatic disease were treated with cyclophosphamide (in 2) and methotrexate (in 2), with complete resolution of their renal disease. All 9 successfully treated patients are alive, with a median follow-up of 58 months. Statistical analysis revealed that creatinine values greater than or equal to 2.0 mg/dl (P less than 0.003) and a serum albumin value less than 2.5 g/dl (P less than 0.02) were associated with a poorer survival. The single strongest variable associated with poor survival was a serum creatinine level greater than 2 mg/dl at presentation, with a median survival of 11.2 months compared to patients with a creatinine level less than 2.0 mg/dl, with a median survival of 56.9 months.