[en] From 1982 to 1987, 165 otter scats samples were collected in the Marais Poitevin area (Western France). Eel was present in 158 of them. In our study area, eel was the main prey of the otter: its relative frequency of occurrence in the otter's faeces amounted to 32.7% and its relative abundance to 40%. We did not find any dietary seasonal variation in terms of eel size or eel number. Prey size ranged from 9 to 65 cm (mean = 28 cm; n = 490) but mostly (75 %) less than 30 cm. In contrast these small individuals made up only 30% of the total eel weight represented by remains in the faeces. Eel size frequency distribution was compared in the otter's diet and in the rivers (data from Legault, 1987: electrofishing and fishing tackles). No significant difference was found, indicating that there was no selection at all in terms of prey size.