The re-emergence ofBrachyspira-associated disease in pigs since the late 2000s has illuminated some of the diagnostic challenges associated with this genus; notably, the lack of standardized antimicrobial susceptibility testing (AST) methods and interpretive criteria. Consequently, laboratories have relied heavily on highly variable in-house developed methods. There are currently no published investigations describing the antimicrobial susceptibility ofBrachyspiraisolates collected from pigs in Canada. The first objective of this study was therefore to develop a standardized protocol for conducting agar dilution susceptibility testing ofBrachyspiraspp., including determining the optimal standardized inoculum density, a key test variable that impacts test performance. The second objective was to determine the susceptibility of a collection of western CanadianBrachyspiraisolates using the standardized methodology. After assessing multiple media, an agar dilution test was standardized in terms of starting inoculum (1–2 × 108CFU/ml), incubation temperature and time, and assessed for repeatability. The antimicrobial susceptibility of a collection of clinical porcineBrachyspiraisolates (n = 87) collected between 2009–2016 was then determined. This method was highly reproducible; repeat susceptibility testing yielded identical results 92% of the time. Although most of the isolates had very low MICs to the commonly used antimicrobials to treatBrachyspira-associated infections, several isolates with elevated MICs (>32 μg/ml) for tiamulin, valnemulin, tylosin, tylvalosin, and lincomycin were identified. Overall, this study underscores the importance of establishing CLSI approved clinical breakpoints forBrachyspirato facilitate the interpretation of test results and support the evidence-based selection of antimicrobials in swine industry.