A method has been developed to isolate X. campestris p.v. carotae in carrot seed lots. The method consists of a low-temperature (5C) satationary aqueous soak of carrot seed in darkness for 18 hr followed by a vigorous shaking of the seed in water containing Tween 20, concentration of bacterial cells by centrifugation (7,796 g for 15 min), and plating of a dilution series of these cells onto a modified Kado and Heskett''s D5 medium. The method yielded repeatable and consistent results in replicated testing of seed lots. The bacterium was detected in 34 of 35 seed samples from infected fields and zero of six seed samples from healthy fields. One naturally infected seed in 10,000 seeds can be detected by this method. This is the first report of direct isolation of X. c. carotae from carrot seed.