Sea food, especially the shellfish can readily be contaminated with pathogenic microorganisms because of the texture of their flesh and also their living habits in the microbe laden habitat they inhabit. In the case of being contaminated with pathogenic bacteria, shellfish pose a serious threat for public health. This study was conducted to investigate the presence of some pathogenic bacteria species such as Aeromonas spp., and Vibrio spp. in the shellfish samples collected from the local fish markets and some of the hotel kitchens in the Dardanelles region of Turkey. During the course of this study, total of 127 shellfish samples were analyzed; 97 of these were mussel and the remaining 30 were shrimp samples. The results obtained from this study determined the presence of pathogenic bacteria species which belonged to Vibrio and Aeromonas genera in 84 samples out of 127 total samples. Among the contaminated samples; 26.7% of the samples were contaminated with Vibrio alginolyticus, 9.4% with Vibrio vulnificus, 0.8% Vibrio parahaemolyticus, and 29.1% with Aeromonas hydrophila respectively. (c) 2005 Elsevier Ltd. All rights reserved.