Mixing control has been discussed in terms of equipment, rotor speed, compound uniformity, and mixing efficiency. It is desirable to have a minimum number of control parameters to describe the effect of mixing on equipment and material properties. This paper has specifically compared work input to time-temperature control specification. The first criterion was that work input give a prediction of Mooney viscosity fter mixing. The results of mixing on two different size Banburys verified that work input per kilogram of rubber is independent of mixer size. Further, mixing at different speeds, but to the same work input level, does not affect the Mooney viscosity of the final mix. Work input, therefore, appears to be a practical measure of mixing and is independent of mixer sizes and mixing speeds. Representative production mixing was carried out using both time-temperature and work input controls. Significant improvements in Mooney viscosity and scorch, oscillating disk rheometer and die swell uniformity result from work input control. The degree of improvement varies, however, and is dependent on the compound, mixing equipment, and mixing cycle. The improvement in uniformity with work input control, therefore, cannot be generalized but must be looked at with consideration to these three parameters. The final objective was to improve efficiency in terms of power and mixing time. Work input control improves efficiency by decreasing cycle time. Savings are dependent on the compound, mixing equipment and cycle; they will vary, depending on these factors.