Firms develop and produce new products based on a product platform in order to meet customers¡¯ diversi-fied needs in today¡¯s rapidly changing market. Developing products based on a product platform can result in a cost reduction due to the commonality among products. However, it can cause cannibalization among prod-ucts due to customers¡¯ perception of the similarity between products. In the previous studies, the cannibaliza-tion effects are examined in a theoretical perspective only. Empirically, a design of a product platform that reduces costs, without taking the cannibalization effects into account, has been studied so far. In this paper, through an empirical study on high technology products, we try to design the optimal product platform that can maximize the cost reduction and minimize the cannibalization effects. We approach this issue from the perspective of the potential customers.