This article examines the status of military and civilian personnel of sending states and international organisations involved in UN peace operations. It undertakes an assessment of relevant customary law, examines various forms of treaty regulation and considers topics and procedures for effective settlement of open issues prior to the mission. The author stresses the need for cooperation between the host state, the sending states and the international organisation in this context. He draws some conclusions with a view to enhancing the legal protection of personnel involved in current and future UN peace operations.