Isolates ofVibrio ordaliiwere recovered from salmon(Oncorhynchus tshawytschaandOncorhynchus nerka)cultured in New Zealand. The fish suffered from clinical vibriosis, from seven outbreaks in five geographically distinct areas. Affected fish showed gross signs and histopathology similar to those reported from North America. The presence of a plasmid, designated pVO1, approximately 30 kilobases (kb) in size, was seen in allV. ordaliistrains examined This plasmid was identical in size and restriction endonuclease cleavage analysis to a plasmid (pMJ101) previously found inV. ordaliistrains elsewhere. After togging pVO1 with the transposon Tn1 from the R plasmid RP4, attempts to isolate plasmid‐less derivatives using a variety of curing agents were unsuccessful. All of the New Zealand isolates possessed identical chromosomal DNA cleavage patterns. These patterns were only slightly different from that of the type strain but substantially different from that of theVibrio anguillarumtype strain.