Fairy shrimp were collected from the Department of Fisheries, Faculty of Agriculture and Natural Resources, Rajamangala University of Technology Tawan-Ok, Chonburi province. A sample of 25 diseased fairy shrimp was investigated. The black parts were removed and identified following Bergey's manual of systematic bacteriology which are based on morphology, staining, oxygen requirements and biochemical tests (Holt et al., 1994) and API20E identification systems (Biomérieux, France). Putative pathogenic bacteria were identified by 16S rDNA sequencing. Scanning electron microscopy (SEM) and the histopathology of diseased fairy shrimp were also used and the results studied. Isolates were stored at -80°C as suspensions in 15% glycerol.