beta 2-microglobulin (beta 2 m) is the major constituent of amyloid fibrils in dialysis-related amyloidosis (DRA), which is considered to be one of the most severe adverse effect of long-term dialysis. In this study we evaluated the efficiency of beta 2 m removal during different dialysis procedures. A total of 45 patients undergoing hemodialysis were divided in five groups: cuprophane dialysis (n = 10), high-flux polysulphone dialysis (n = 10), postdilutional hemodiafiltration (n = 10), conventional postdilutional hemofiltration (n = 10) and predilutional on-line hemofiltration (n = 5). Serum level of beta 2 m was determined before and after different procedures using ELISA. In the group of patients on cuprophane dialysis was registered an elevation of beta 2 m and of 16.8 +/- 11.4% on the average. Serum level of beta 2 m was decreased following all other procedures on the average of 40.7 +/- 16.4% after high-flux polysulphone dialysis, 42.0 +/- 13.7% after conventional hemofiltration, 64.7 +/- 9% after hemodiafiltration and 67.9 +/- 10.1% after predilutional hemofiltration. The best removal of serum beta 2 m was realized by predilutional hemofiltration. Also, we have noticed that patients treated with high-flux synthetic membranes in the longer time-period have lower predyalisis value of beta 2 m compared to patients treated with cuprophane membrane. Further long-term studies will be necessary to conclude whether these procedures could be successful prophylactic and/or therapeutic regimen for dialysis-related amyloidosis.