The Machining-producibility Evaluation Method(MEM)for cutting and grinding was developed to assess design quality for easier processing of parts and products, thus for productivity improvement and manufacturing cost reduction. It features the followings : 1.Quantitative evaluation using easy to understand 100 point scale and accurate processing cost estimation. 2.Method is easy to both learn and use, using 12 basic evaluation element symbols. 3.Concurrent calculation of processing cost for workshop with indices. This paper describes the basic theory of the method.