Fractional and group composition of tar, obtained by thermolysis of wood lignins in oxidizing medium (5-6per thousand of O₂) and cotton husk lignin in oxygen-free medium at 450- 500°C was studied on the laboratory equipment. Significant differences in the yields and composition of the tar were established, largely depending on the contact of residual carbohydrates in the lignins. Deposit tar from cotton husk lignin contained up to 45per thousand aliphatic compounds with surface- active properties.