This study was intended that the biochemical patterns, bioserological characteristics, resistance of antibiotics, and transferable resistance patterns of 35 Escherichia coli strains from 79 fish and shellfish samples in marine markets from August to October, 1995. The Standard plate count, coliforms and fecal coliforms were also counted in the 79 cases and analysed the correlationship each other. Geometric means of Standard plate count in seawater fish, shellfish, mollusca and crustacean were 1.4 × 105 CFU/g, 4.0 × 10^5 CFU/g, 2.4 × 10^5 CFU/g, 4.7 × 10^5 CFU/ g, and those of coliforms were 1.3 × 10¹ CFU/g, 4.8 × 10³ CFU/g, 8.9 × 10² CFU/g, 5.8 × 10³ CFU/g. There were no fecal coliforms in the fish and mollusc. However, the geometric means of coliforms in the shellfish and crustacean (1.1 × 10¹ CFU/100g, 10 CFU/100 g) were less than those of fish and mollusca. The important biochemical characteristics of E. coli distinguished from the shellfish and crustacean were motility, ornithine decarboxylase, mucate, esculin. The fermentative properties of E. coli were also sucrose, salicin, sorbitol, and raffinose. Of 35 isolates of E. coli, 13 strains (37.1%) showed the pathogenic O antisera, which were O:27 3 strains (23.1%), O:159 2 strains (15.4%) and O:148, O:119, O:142, O:158, O:136, O:18, O:128, and O:168 1 strain (7.7 %), respectively.