Abstract: Polymer sheet, strip, or film is compression rolled continuously at ambient temperature between rollers under semiboundary or boundary lubrication conditions to effect a single pass reduction in the thickness of the polymer material of from 19/20 to 1/20 of the original thickness. Polymer films formed by this compression rolling process exhibit increased modulus (stiffness), tensile strength, and (in the case of non-opaque materials) enhanced clarity. The circumferential speed of the rollers is maintained essentially equal to the linear speed of the thermoplastic sheet material passing between the rollers and the film rewind tension is maintained in the vicinity of the elastic limit of the material exiting from the rollers.