The experiments aimed to determine the effect of composting process of selected municipal wastes with various admixtures (starch, edible oil or urea) on the content of zinc, manganese, copper and iron forms in the obtained composts. The object of research was raw “heating” compost from plants and other biodegradable wastes (marked with 20 02 01 code in the waste catalogue), leaving biostabilizer chamber of the composting plant operating in MUT-Kyberferm system. Extraction of Zn, Mn, Cu and Fe was conducted according to McLaren and Crowford procedure. Additionally, extraction of heavy metals from separate weighed portions of heavy metals was conducted for 30 days be means of redistilled water. Heavy metal content in the obtained extracts was assessed using ICP-AES method on JY 238 Ultrace apparatus (Jobin Yvon). Total content of zinc, manganese, copper and iron in the analysed composts does not exclude their application in agriculture. The kind of element has a greater influence on the content of analysed trace elements in the individual fractions than the supplement of starch, edible oil or urea used for the composting. A significant increase in zinc, manganese and iron content was assessed in the water extract after 30 days of extraction in comparison with the content determined in the water extract obtained according to McLaren and Crowford procedure. Copper content decreased.