This article describes humanitarian issues and dilemmas faced by the ICRC in dealing with persons unaccounted for during and after armed conflict. It gives a short overview of the relevant rules of international humanitarian law and emphasizes the respect of legal obligations to prevent disappearance and separation and to alleviate the plight of families of missing persons. Best practice in the field of conflict-related disappearances would be respect of the law. Raising awareness of international humanitarian law, cooperating with the belligerents, assisting them to respect their obligations and acting as neutral intermediary between them in view of facilitating compliance are the main functions of the ICRC in this regard. As belligerents often do not respect or sometimes even distort their obligations, the institution frequently has to substitute itself in fulfilling their duties. The article shows practical examples and proposes systematisation and development of ICRC activities related to the missing issue.