Greenlandic blood feuds were based on a moral obligation which might logically imply endless feuds between the families involved. In actual practice, however, the feud normally ended with the implementation of the first murder of revenge. Ideologically speaking, however, there was a moral obligation to take revenge, implying the possibility of a continued feud after each murder of revenge. Pospisil's definition may be applied to Greenlandic practice. The ideology of blood feuds resulted partly in a certain social insecurity, partly in a number of actions intended to prevent revenge, both aspects to be treated in connection with the phenomenon of blood feuds. The socio-cultural background of these preventive actions constitutes one theme. Another theme is the change in the attitude of Christianized Greenlanders to the possible effects of blood feuds. The introduction of Christianity in Greenland produced a change of view with respect to blood feuds which are now prohibited. This appears from two sagas of fairly recent date where the moral obligation to take revenge gives rise to a new phenomenon: the "inherited" blood feud ending up within the framework of the family itself. However, in spite of Christian influence the sagas do not reject the traditional obligation to take revenge. This obligation has its positive aspects in connection with traditional values which retained their validity for several decades, Christian influence notwithstanding.