The purpose of this study is to explore volunteer-based entrepreneurship mentor network and particularly examine the motives of people being part of the network. The framework of this study is a business plan competition called Venture Cup Finland, aiming to contribute to creating new start-up companies. The study aims to create new understanding of non-profit organization in the field of entrepreneurship as well as to study the volunteers taking part in the professional mentor network and their motives. The study comprises a theory review on volunteerism, the motives of volunteers’ and business plan competitions’ contribution to growth entrepreneurship. The empirical data of this study consists of a qualitative case study. The results indicate that this kind of network is not successfully managed with the traditional hierarchic non-profit way by using extrinsic motives. In addition, intrinsic motives and possibility to influence within the network are key elements in attracting relevant people to the mentor network.