A total of nine Vibrio tapetis strains acquired from France, the United Kingdom and Norway were studied for their plasmid content. All the isolates contained from two to four large plasmids, ranging from approximately 60 to 100 kpb. in size. These plasmids were subsequently subjected to restriction fragment length polymorphism analysis (RFLP). Using the EcoRI enzyme, three different restriction patterns were demonstrated, two of which were closely related. On the basis of RFLP patterns, the strain from Norway differed noticeably from the French and British strains.