Combined kinetic theory-hydrodynamics treatment has been proven effective in the prediction of biomolecule dynamics, generally if a single biomolecule is present in the bulk solvent. But the validity of such a theory in many physiological conditions is controversial. In the present study, a sample protein surrounded by other large biomolecules is approximated as the protein in a cylindrical nanopore. The hydrodynamic radius of the protein is chosen as an indicator to check whether one of the widely used kinetic theoryhydrodynamics relation namely Stokes-Einstein-Debye relation, is genuine for confined conditions of the protein. It has been found that Stokes-Einstein-Debye relation cannot be satisfied by the protein if confinement dimensions are very close. The reason for the violation can be attributed to van der Waals interaction between pore and the protein. © 2019, Avestia Publishing.