Thermal analysis was carried out on peat and its residues after successive separation of water-soluble substances (6.8%), bitumens (3.9%), hemicellulose (5.9%), humic acids (33.4%) and cellulose (21.5%). The primary peat gives two exothermal effects, at 290° and at 275°. After humic acid and cellulose separation, respectively, the second effect decreases and then disappears completely.