From September 2009 until March 2010 the diet of the neotropical otter in La Vieja River, an affluent of the Cauca River, was studied. Otter’s feces were collected twice a month in plastic bags along a 33 kilometers transect from Puerto Samaria (Department of Quindio) to Piedras de Moler (Department of Valle del Cauca). In total 686 otter feces were collected which were washed, sifted and compared with a reference collection. Thirteeen food categories were recognized where fish were dominant (11 categories). Apteronotus sp. showed the most frequency of occurrence (37.43 %), followed by Hypostomus sp. (33.28 %) and Rhamdia quelen (30.50 %). Other fish species predated by the otter in less proportion were: Ichthyoelephas longirostris (23.84 %), Ancistrus sp. (22.91 %). Following the aforementioned fish species, insects were the next most important group; the Corydalus sp. (14 %), and in less proportion snails (1 %) and mammals (0.46 %). Most preys were accidental (77 %) and incidental (23 %). The otter hunts the same preys in low rainfall season as well as in high rainfall season (Rs = 0,91; n = 13 p < 0.00001, Jaccard Index Ij = 0,92).