A method for controlling a refrigerant distribution in a vapour compression system, such as a refrigeration system, e.g. an air condition system, comprising at least two evaporators. The refrigerant distribution determines the distribution of the available amount of refrigerant among the evaporators. While monitoring a superheat, SH, at a common outlet for the evaporators, the distribution of refrigerant is modified in such a manner that a mass flow of refrigerant to a first evaporator is altered in a controlled manner. The impact on the monitored SH is then observed, and this is used for deriving information relating to the behaviour of the first evaporator, in the form of a control parameter. This is repeated for each evaporator, and the refrigerant distribution is adjusted on the basis of the control parameters. The impact may be in the form of a significant change in SH. Alternatively, the control parameter may reflect a change in SH occurring as a result of the modification of the distribution of refrigerant.