The effect of TPA polymer (thermal polyaspartate anion) on the physical-chemical properties of diesel fuel - density, kinematic viscosity at 40 degrees C, moisture content, total acid number, thermal combustion, 90 vol.% distill-off temperature, and cetane number - is studied. It is shown that the moisture content and total acid number decrease considerably when TPA is introduced, while the heat of combustion and cetane number increase considerably, which improves fuel quality.