The article deals with some of the new legal issues arising in the Mrkšic et al. Appeal Judgment, with particular regard to the responsibility of the accused Veselin Šljivancanin for his role in the attack against Croat prisoners of war (POWs) that occurred in Ovcara, Croatia, in 1991. The ICTY Appeals Chamber shed light on the nature and scope of the individual duty to protect POWs under Articles 12 and 13 of Geneva Convention III and held that an agent of the Detaining Power entrusted with custody and control over POWs is under the duty to ensure their safe transfer even when he no longer has custody and control over them. In convicting Šljivancanin for his failure to protect the POWs, the Appeals Chamber also clarified the elements of aiding and abetting by omission. However, the Appeals Chamber’s failure both to characterize the armed conflict in Croatia and to clarify on what legal grounds the captured Croats were entitled to POW status is open to criticism.