This study shows the possibility of using birch bark, a by-product of plywood production, for preparing polyurethane foam. A birch bark lignocellulose component – inner bark – was liquefied to obtain a polyurethane raw material – polyol mixture. Outer bark, containing valuable biologically active pentacyclic triterpenes (betulin, lupeol, betulinic acid, etc.), after extracting those compounds, was subjected to hydrothermal treatment in alkaline medium, and the other main inner bark component – suberin – was depolymerised. The obtained suberinic acid triethanolamine ester, as a polyol component, was used for polyurethane foam synthesis. Both types of polyols gave polyurethane foams with good physical properties. Such a complex approach has shown that it is possible to prepare new products with a high added value from waste natural raw materials.