First, this paper will analyse the information given by the ancient literary sources – from the Greek tragedians to the Orphic Argonautica – on the outrageous murder of Apsyrtus. The main goal of the paper, however, is to investigate the outset and the dissemination of the toponomastic traditions which are inspired in antiquity by that cruel delict, namely the so called Apsyrtides islands in Northern Adriatic and the towns Apsaros and Tomi at the Pontus Euxinus. My research shows that only from the fourth century BC onwards the bloody event left traces in the toponomastic tradition, which is mostly concerned with the representation of Apsyrtus in his adult age. Moreover, the different locations of the murder are of course connected with some return routes of the Argonauts. Finally, it is noteworthy that there are also cases of contaminations between different traditions, as usual in ancient mythology.