With the transformation of chemical industries from being process-focused to being product-focused, there has been remarkable progress and efforts in the field of computer-aided chemical product design. This chapter provides an overview of the various mathematical tools used for chemical product design. This chapter focuses on the utilization of mathematical programming techniques to identify/generate molecules with optimal/desirable properties. Various optimization algorithms appropriate for dealing with single and multiple objectives are described. In order to utilize such optimization techniques, a discussion of design of experiments that maximizes the collection of information is presented. The data gathered is utilized to develop property models that relate molecular structure to properties and are incorporated in the optimization procedure. A discussion of molecular descriptors, which capture structural features, is also presented. Also, the two main approaches for solving molecular design problems, i.e., the forward approach and the inverse approach, are presented. These methods are compared to the traditional product design approach, which relies primarily on experiments. The consideration of uncertainty in the computer-aided design procedures is also discussed in this chapter. Finally, further development possibilities in the field of chemical product design are discussed.