Concentrations of Al, B, Ba, Cd, Co, Cr, Cu, Fe, Ga, Hg, Li, Mn, Mo, Ni, Pb, Se, Si, Sr, Tl, V, Zn, Ca, K, Mg, Na and P in the livers of marine mammals obtained from by-catches or stranded on beaches on the Polish Baltic coast were determined by ICP-MS or ICP-AES and CV AAS. Interspecific diversity with respect to the contents of these elements was found in cetaceans and pinnipeds. The diverse Cd contents in the livers of these mammals can be attributed to the variable concentrations of this element in their food. Mercury was correlated with age and can reach high concentration associated with higher level of Se in older specimens. No significant relationships were found between concentration of the chemical elements studied and nutritional status/condition of the Baltic harbour porpoises as well as between their concentration in specimens from the Gulf of Gdańsk and open Baltic. It seems that the nutritional and health status of the specimens studied is generally enough good since the specimens studied were not stranded on beach because of starvation but almost incidentally caught in salmon gill nets. Strong correlations were found between the macroelements analysed, i.e. for the Ba-Ca-Sr, Ca-K, Ca-Mg, Mg-P, Zn-Mg and Zn-P assemblies. Significantly higher content of Al was found in males of harbour porpoises.