The primary interest of the automotive and of the rubber industry in so-called synthetic rubbers is to obtain products which will stand up under service conditions in which present rubber compounds either do not perform satisfactorily over their entire expected life, or are approaching their limit; or because of these factors, are limiting automotive engineering development. In addition, the last few months have seen a trend of thinking toward a nationalistic program of at least partial self-sufficiency, in case of emergency, or a possibility of the limitation of the poundages of crude rubber available to us at an economic price. The subject “The Use of Synthetic Rubber in the Automotive Industry” is consequently being considered in the light of both viewpoints. Activity in the field of synthetic rubbers as far as laboratories in this country are concerned has increased considerably over the last three years, and it is quite likely that the data and viewpoints herein presented on present polymers may very well be obsolete within a matter of months, and certainly within a year or two, with the appearance of new polymers and modifications of present ones. The object of this paper is consequently to summarize the present state of affairs regarding materials now available. The literature on synthetic rubbers is abundant as to the preparation of the various kinds and varieties, their compounding, and the characteristics of fabricated products. A very excellent and interesting summary is that by Wood. From a general viewpoint, the article entitled “Synthetic Rubber” in the August issue of Fortune is very much to the point. The characteristics of Neoprene are well known. Those of the butadiene types have been described in several articles by Stöcklin and by Koch. Similarly other products have been described. Anderson and Garner and Westhead have given some comparative data on Neoprene and Buna types. In view of these articles, the present paper appears superfluous. It has been pointed out by Wood, however, that it would be desirable to have additional confirming data on a comparable basis on the materials now available. It has been with the hope of supplying such data, at least in part, and particularly as applied to usage of synthetic rubbers in the automotive field, that the authors continued with the preparation of this paper.