The multidisciplinary nature of organisational new product development (NPD) suggests that the development of successful new products is dependent upon the individual and combined efforts of various functions. Despite being recognised as two highly important disciplines in NPD, marketing and design have received little empirical examination of their roles in the NPD process and their effects on NPD outcome. In order to address this gap within the literature, the objectives of this thesis were to assess the presence of marketing and design in NPD, explore the nature of the marketing-design relationship, and examine the effects of marketing influence, design influence, and the level of marketing-design connectedness on NPD outcome. The study was set within the New Zealand context and data was collected via a web-based survey from 91 manufacturing firms that adopted both marketing and design in their NPD programmes. The results showed marketing and design to be two highly influential functions in NPD. Both functions were also found to be strongly involved in the NPD process. A positive relationship was found between marketing and design’s functional influence, which suggested the possibility of an interdependent relationship between the two disciplines. Finally, marketing and design were found to affect different aspects of NPD outcome, with marketing positively affecting product innovativeness, and design positively affecting process proficiency and financial performance. The research has implications for the future development of marketing, design, and NPD theories, as well as for managers seeking to improve their NPD activities through the alignment of their marketing and design functions.