Vibrio spp. in the marine environment play an important role in biodegradation, nutrient regeneration and biogeochemical cycling. These microorganisms are normal residents in coastal waters and their numbers depend on environmental parameters. The qualitative and quantitative composition of culturable Vibrio spp. in water samples from the Northern Ionian Sea (Italy) was investigated. The study was carried out from December 1999 to November 2000 in 10 stations along the coast line between Castellaneta Marina and Santa Maria al Bagno. Seasonal distribution of culturable vibrios densities showed the highest values during the summer-autumn period. Furthermore, in all the examined sites vibrio abundance was higher at the stations nearest the shore. During the sampling period 387 Vibrio spp. strains were isolated. Vibrio mediterranei was the predominant species, V. nereis and V. harveyi also represented two consistent components of the isolated culturable vibrio community. V. alginolyticus and V. parahaemolyticus showed a mean isolation percentage of about 7%. Recovery of some vibrio species was correlated with temperature. Data provided in this study will improve our understanding of the distribution of Vibrio species in the Northern Ionian Sea.