We present a model of the waiting list for residential care for the mentally disabled in the Netherlands. The model is a linear stock-flow model and distributes the mentally disabled over different living situations. It includes institutional and semi-institutional care explicitly and ambulatory and other types of care implicitly. Four scenarios are simulated, exploring possible future developments. Scenarios differ in the mortality rate of mentally disabled, the supply and use of ambulatory care and the possible effect of uncertainty in the data. Results show that unless continuous efforts are made to decrease the inflow in the waiting list and to supply extra care as well as extra alternative care. the waiting list for residential care will continue to grow.