The purpose of this paper is to investigate the feeding habits of Parapenaeus longirostris in the Greek and Italian Ionian Sea. The individuals were caught from September 1999 to July 2000 on a seasonal basis (except winter) in the Greek Ionian Sea, and in August 2000 in the Italian Ionian Sea. A total of 324 males and 309 females of P. longirostris were analysed. A comparative analysis of the diet and feeding activity was made, taking into account sex, season, size classes and study area as factors influencing the feeding habits of the species. Dietary diversity was also estimated. P. longirostris displayed a high feeding preference on a large variety of bathypelagic, benthic and endobenthic preys, mainly polychaetes, crustaceans and molluscs. No clear differentiation in the feeding behaviour between sexes, including diet composition and feeding activity, was observed. The increased feeding activity during spring for males and spring-summer for females could possibly be attributed to metabolic processes. This species undergoes changes in its feeding habits with ontogeny. Larger specimens were more efficient predators than smaller ones, possibly because of their greater swimming ability. The increased feeding activity in the Italian Ionian Sea is possibly related to the different environmental conditions.