Interdependence between Technically Trained Managers and Marketing Managers in new product development (NPD) teams is inherent, though few studies have investigated its effects within such teams. Here, interdependence is disaggregated into two underlying dimensions — the dependence of the Technically Trained Manager on the Marketing Manager, and the dependence of the Marketing Manager on the Technically Trained Manager during the project. Our model is tested using data from 184 Technically Trained Managers from Australian companies involved in NPD. The results suggest that interdependence is an important contextual variable during NPD projects. Senior managers should communicate its importance to NPD team members because of its positive effects within the NPD team. Where the Technically Trained Manager and Marketing Manager recognise their interdependence, they engage in more frequent, and more bidirectional communication. This is important because more effective communication between these two managers positively influences the quality and effectiveness of their working relationships, which in turn can increase NPD project success.