This survey was carried out to investigate the infection rate of Riemerella anatipestifer from domestic ducks by isolation. A total of 145 samples (nasal swabs and carcasses) were collected from farms to examine the biochemical properties and antimicrobial susceptibility test from November 2006 to February 2008. Riemerella anatipestifer was isolated from 13 of 145 sample and isolation rate was higher in the ducks below 25 days (76%, 10/13 isolates) than those over 26 days (23%, 3/13). However, there was no significant difference in isolation rate between region. The biochemical properties of isolate were Gram negative (-), non-fermentative rod that grows fastidiously on routine media. In the test of antimicrobial drug susceptibility the isolates were susceptible to tetracycline(100%), enrofloxacin (77%), ampicillin (70%).