Fully atomistic models of very thin films of amorphous polyethylene are studied. The density profile of the thin films shows that the surface layer is thicker than the result obtained previously for thin films of poly(1,4-cis-butadiene), using a similar method. This difference in thickness of the surface layer is attributed to the fact that polyethylene is a stiffer chain than poly(1,4-cis-butadiene), as reflected by the difference in their characteristic ratios. The C-C bonds are randomly oriented in the interior of the film, but in the outer portion of the surface layer they have a slight preference for an orientation in the plane of the film. The contribution of the internal energy to the surface energy of the film is estimated to be 20 erg cm(-2), which is lower than the experimental value of 26 erg cm(-1) reported in the literature for the surface energy. The roughness of the surface varies from 0 to 6 Angstrom as the radius of the spherical probe used in the measurement becomes smaller.