Metallothionein (MT) from rabbit liver was analysed by differential pulse polarography (DPP with DME), cyclic voltammetry (CV), square wave voltammetry (SWV), and chronopotentiometric stripping analysis (CPSA) with hanging mercury drop electrode (HMDE) under various conditions. The highest sensitivity of the MT determination was obtained with CPSA which produced a well developed peak H due to catalytic hydrogen evolution at highly negative potentials. The highest peak H was obtained in borate buffer at pH 7.6. In this medium subnanomolar concentrations of MT were detectable. In the adsorptive transfer stripping (medium exchange) experiments determination of few femtomoles of MT in 5 ml aliquots of the analyte was possible. CPSA determination of MT in various tissues of carp (Cyprinus cyprio) yielded values in agreement with the published data.