Bordetella bronchiseptica, isolated from rodent nasopharygeal swabs, failed to produce characteristic colonies after 24 hours incubation at 37 degrees C. 4-7 days incubation at 37 degrees C was required to achieve positive motility test results, when isolates later identified as B. bronchiseptica were tested by Craigie tube and soft agar stab methods. The biochemical tests used to identify suspected B. bronchiseptica are specified.