In radioimmunological estimation of beta 2-microglobulin (beta 2m) significant higher serum values were found in 36 dialysis patients (44.4 +/- 20.3 mg/l) in comparison with healthy probands (1.5 +/- 0.2 mg/l). A significant relation to the duration of dialysis, diuresis, symptoms of the musculo-skeletal system, but not to radiologic changes or bone biopsy findings could be seen. Post mortem examinations carried out in 21 dialysis patients revealed AB-amyloid deposits in synovial tissue of different joints (particularly shoulder and hip joint) or intervertebral discs in eight patients (age 48 to 73 years, dialysis duration less than four years) without correlation to serum beta 2m level or radiographically suspect areas. In the tissue of cervical spine or intervertebral discs of two patients suffering from destructive spondylarthropathy no amyloid could be detected. These results suggest that AB-amyloid may occur in elderly patients early in the course of hemodialysis and may be asymptomatic in most cases.