In this work the rheological and structural properties of n-hexadecane have been studied by molecular dynamics simulation. The model consists of two structured atomic walls between which the fluid is sheared by moving the walls in opposite directions. The fluid consists of chains of n-hexadecane molecules. Each molecule has 16 interaction sites where each site on the molecule represents a CH, or CH, group. The Lennard-Jones potential governs the intermolecular interactions. Stretching, angular and torsional potentials are used for the intramolecular interactions to preserve the integrity of the molecules. An isothermal simulation of the Couette shear flow is conducted to reveal the rheological properties of n-hexadecane at high Weissenberg numbers in films as thin as 1 nm. The results obtained show an increase in the average viscosity of hexadecane as the film thickness is decreased to scales comparable to the molecular diameter of the chain segments. These results agree with recent experimental findings for very thin films, revealing shear thinning and normal stress difference effects which are an indication of non-Newtonian behaviour. Structural properties such as the density profiles, bond angle and dihedral angle distribution functions and average end-to-end distance of the molecules are obtained for alms of different thickness and at different shear rates. The effects of the wall-fluid interaction strength on the fluid properties are also investigated in different adsorption limits. It seems that adsorption is a determining factor in the properties of these ultrathin films. The results indicate different shear responses depending on the adsorption limit of the surface.