This work presents the electrothermal atomic absorption spectrometric (ETAAS) determination of aluminum (AI), copper (Cu), iron (Fe), lead (Pb), vanadium (V) and zinc (Zn) in whole blood, blood components, bone and urine specimens from hemodialyzed azotemic patients and healthy subjects, and in certified environmental reference materials. Prior to the ETAAS analysis, test portions of the samples were diluted at different ratios in appropriate solvents: (i) whole blood, blood plasma, blood serum and red blood cells, in 0.1% v/v Triton X-100; (ii) urine, in 0.1% v/v Triton X-100 + 0.01 mol 1-l nitric acid; and (iii) mineralized samples (e.g., bone, pond sediment, vehicle exhaust particulates and sargasso), in 0.01 mol 1-l nitric acid. For Al, Cu, Fe'and Zn, the diluent solutions also acted as the analyte isoformation solutions. For Pb and V, the analyte isoformation solutions were 0.5 mg 1-l of palladium +2% m/v of citric acid and 0.1 mg 1-l of palladium +2% m/v of citric acid in 0.01 mol 1-l nitric acid-0.1% v/v Triton X-100, for the former and for the latter, respectively. These analytical isoformers were not combined directly with the specimens in order to eliminate any precipitate formation, particularly with whole blood and its components. The detection limits (3a, pg l-l), were 0.5 (Al), 0.3 (Cu), 0.5 (Fe), 0.1 (Pb), 0.4 (V) and 0.1 (Zn). Accuracy was evaluated by using whole blood, human serum, freeze-dried urine, pond sediment, vehicle exhaust particulates and sargasso reference materials. For all metals present in real samples, precision was better than 3.0% R.S.D. The proposed methods were used to establish the metal concentrations found in the clinical samples under consideration. The methods were free from interferences, reliable and reproducible.