A scheme has been developed for calculating the flow temperature, Tf, of a system containing a polymer and nanoparticles. The chemical structure of the polymer and nanoparticles, the intermolecular interaction between polymer and nanoparticle when the latter is modified with polar groups, the van der Waals volume and the molecular weight of the polymer, and the concentration and shape of the nanoparticles were taken into account. The dependences of Tf on the radius of the nanoparticles, their concentration, and the number of polar groups grafted to their surface have been established. The calculation scheme has been computerised and is a separate option in the ‘Kaskad’ computer program developed by INEOS.