The nurse rostering problem consists in assigning working shifts to each nurse on each day for a certain period of time. In particular, for the Valparaíso Clinic Center, the problem comprises about 1600 assignments that must consider requirements related to minimal area or floor allocation as well as legal regulations. This planning is a difficult and time consuming task that currently is done by hand yielding often unsatisfactory results. In this paper, we provide a description of such a real-world problem and we show how it can be modeled and solved with constraint programming. Using this approach we provide an automatic generation of such rosters in a few seconds instead of by hand in some days. © 2011 Springer-Verlag.