PURPOSE – The aim of this paper is to investigate the effects of task and informal networks and their interaction on cooperative types of employee behaviour. DESIGN/METHODOLOGY/APPROACH – Two studies are used to examine the research question. The first dataset consists of book-length ethnographies providing information at the team level. The second dataset is gathered through a survey across ten different organisations and provides information at the employee level. Both datasets are analysed using OLS regression. FINDINGS – Cooperative behaviour is positively affected by task and informal interdependence relationships. However, when employees have task and informal interdependence relationships with co-workers, they may show less cooperative behaviour. RESEARCH LIMITATIONS/IMPLICATIONS – A major limitation of this study is that it was not possible to include information about the structure of the networks in which the employees are embedded. The study provides evidence for the existence of exchange relationships between the employee and the team. Besides that, the study shows the importance of including formal and informal networks to study cooperative behaviour of employees. PRACTICALl IMPLICATIONS – The findings provide practical information about how to manage cooperation within teams. Cooperative relationships can be created by either creating task or informal interdependence. Besides that, managers should strike a balance between task and informal interdependence. ORIGINALITY/VALUE – Existing research tends to focus on the effects of one type of network on behaviour. This research shows that different networks may affect employee behaviour at the same time.