Six piles of compost consisting of sewage sludge, grass and branches for content of macro- and microelements and heavy metals were tested before and after 50 days of composting. The increase in the efficiency of the composting process resulted in a decrease in the content of C, N and H, and in an increase in the concns. of P, B, Ba and Zn in the composted material. The content of biogenic elements, macro- and microelements as well as heavy metals did not exceed the limit values for org, fertilizers.