The diet of Schilbe intermedius of the right bank of Pool-Malebo (Congo Brazzaville) was studied by examining the stomach contents of 942 individuals captured using the cash nets. Three stations were sampled monthly from January 2010 to December 2011. The analysis covered individuals with a standard length ranging from 23.93 to 129.3 mm according to sampling stations, hydrological season and fish size. . The preponderance index combining the numerical occurrence percentage and the weight percentage was calculated. The percentage of emptiness is 27%, fishes are the main preys consumed by Schilbe intermedius with a preponderance index equal to 64%. There was variation in diet according to the season and the specimens size. The correlation coefficient of Spearman showed that the proportions of the different foods vary according to the size of the specimens (rs = 0.42, p = 0.05). Schilbe intermedius is insectivorous in small juveniles that are becoming piscivorous predators in older, larger specimens.