Background: Return to work (RTW) after sick leave is considered necessary to support the employees' health. Cooperation between employees and employers may encourage employees' RTW, but is hampered by bottlenecks that we do not completely understand. Dutch legislation means to support this cooperation and allows trying RTW during two years. The Resource Dependence Institutional Cooperation (RDIC) model has been developed for studying cooperation in public health. Study aims were to get insight into the degree of cooperation between Dutch sick-listed employees and employers, how this (lack of) cooperation can be understood, and how valid the RDIC model is for understanding this (lack of) cooperation. Methods: This qualitative study was based on in-depth interviews with 8 employees and 8 employers. Employees reported sick for 1.5-20 months for various reasons. Interviews were analysed using an interpretative approach and pattern matching. Results: Cooperation was lacking early during sick leave. Later on there were regular meetings, but employers decided about RTW without consulting the employees. Particularly employers were motivated to cooperate during the first year, while employees were especially motivated during the second. This could be understood by experienced dependence; employees (first year) and employers (second year) did not consider cooperation to be important for achieving medical recovery (employees) or RTW (employers). These divergent goals may be understood by personal norms about the timing of medical recovery and RTW. Legislation was particularly effective regarding employer behaviour in year 1 and employee behaviour in year 2. Employees distrusted their employers during the first year, while employers reported to distrust the employees during the second year. Besides, employees and employers experienced a moderate ability to cooperate. This could be understood particularly by having moderate knowledge about legislation. The RDIC model appeared to be valid to understand the cases studied, but ...