New product development at inter-firm level is clearly an important topic for researchers and managers. Although many papers have reported the importance of collaboration in NPD the collaboration involving partners with different technology endowments and how many small firms have managed to achieve a status of reciprocity have remained unaddressed. In this exploratory study four multinationals and sixteen suppliers were visited and their top executives interviewed to determine the key success factors of collaborative product development as perceived by suppliers. Four case studies were prepared in order to exemplify the supplier’s perceptions to inter-firm product development involving differently endowed firms. The main findings are clear: suppliers and clients have different perspectives and play different roles due to the bargaining power exercised by the latter and by the fight for reciprocity of the former.