Alternations in trace elements concentrations are intensively studied because of their possible role in pathogenesis and progress of diseases. Three groups of patients were investigated: haemodialysis patients (HD) (n = 17), continual ambulatory peritoneal dialysis patients (CAPD) (n = 11), and control group of blood donors (n = 12). They were analyzed for Se, Zn and Cu concentration in plasma and erythrocytes by inductively--coupled plasma mass spectroscopy. Distribution of analyzed elements between these blood compartments was found different in all groups of studied patients. Erythrocytes were enriched by Se (twofold higher concentration compared to plasma) and by Zn (10-20 fold higher concentrations compared to plasma). On the other hand, human plasma was enriched by Cu (approximately twofold higher concentration then in erythrocytes). Results of analyses were processed by multivariate analysis of variance (MANOVA). When only results of plasma analysis were involved into MANOVA, differences between HD patients and other two groups were found whereas CAPD and control group were not distinguished each other. However, these two groups were mutually differenced when MANOVA comprised all trace elements concentrations: both plasma and erythrocytes. Methods of multivariate statistic are able to study not only the individual variables but even their mutual relations and their medical applications are very useful.