Is a Dutch court able to vary the terms of an English trust by applying English trust law if a Dutch court does not normally have such a wide discretionary power? Is a Dutch court able to apply a rule from Moroccan family law that designates the court itself as custodian if Dutch law does not confer such a task on a court? Is a Dutch court able, when it is asked to pronounce a divorce on the basis of Jewish law, to act in a religious capacity? These questions show possible limits of the judicial function in private international law matters. Private international law doctrine knows several theories that are intended to provide guidelines for answering these questions. After having explored those theories, the author concludes that at least three limits of the judicial function can be distinguished. If a Dutch court concludes that in applying the foreign law that has been designated by the Dutch conflict rules it would encounter one of these limits, then the court is not competent from a constitutional point of view to apply that foreign law, in conformity with the purpose intended by the foreign legislature. However, this does not mean that the court has no competence to give a decision at all. The author stresses that it is desirable, and sometimes even compulsory, that the court looks for an alternative decision to prevent parties from being sent home ‘empty-handed’.