An approach for product line design is presented in which a line of products is selected for launching into the market. In the approach, the product line design is viewed as a selection process with two main stages: design alternative generation and design alternative evaluation. The focus of this paper is on the design alternative evaluation stage. Issues considered include a large variety of customer preferences, market competitions, multiple business goals, uncertainty, and commonality among the alternatives in a product line. Because of the combinatorial nature of the problem, genetic algorithms are used in the design evaluation stage. Product line design selection of a cordless screwdriver is used as a demonstration example. However, the emphasis in the example is on the approach and not in the details per se.