The first ever Australian outbreak of equine influenza (EI) in 2007 resulted in the issuing of biosecurity guidelines by animal health departments. However, like any policy concerning human behaviour modification, the uptake of biosecurity measures is dependent on a number of determinants such as the perceived efficacy of the protective measures. We aimed to identify factors associated with high perceived biosecurity efficacy. In 2009, 200 face-to-face interviews were conducted with horse owners from highly EI affected regions of New South Wales (NSW), randomly selected from lists of infected and uninfected properties obtained from the NSW Department of Primary Industries. The interview included questions about biosecurity perceptions and information sources. Perceived biosecurity efficacy (low, high), as determined by participants’ responses to a 17- item question on the efficacy of various biosecurity measures, was used as outcome for binomial logistic regression analyses. Most participants (83%) perceived biosecurity efficacy to be high. Men and women and people of different ages did not perceive efficacy differently, however, the 123 (62%) participants, who experienced EI infection in their horses during the 2007 outbreak were less likely to deem biosecurity measures effective (OR = 0.24; CI: 0.07-0.68; p = 0.006). Interestingly, participants who received biosecurity information from a veterinarian during the EI outbreak were 5.5 times more likely to believe in the efficacy of biosecurity measures (CI: 2.24-14.18; p <0.001). Veterinarians should be considered as information providers when designing infection control programs, in order to alter horse owners’ perception regarding biosecurity efficacy and to ultimately increase their biosecurity compliance. Acknowledgements: This research was funded by the Rural Industries Research and Development Corporation (RIRDC).