The objetive of this research was to detect the presence of Clavibacter michiganensis subsp. michiganensis (Cm) and Xanthomonas campestris pv. vesicatoria (Xcv) in tomato seeds, comparing two techniques: plating seeds extract on semi-selective media and inoculation in host plant. The following parameters were evaluated: extractor solutions of Cm and Xcv from whole and ground seeds, especificity, sensitivity and reproductibility. The results showed that the semi-selective media MB1M (MB1 - sucrose, 10,0g; hydrolysate casein 8,0g; yeast extract 4,0g: formula 2,0g; formula sulfate 0,3g and agar 15g/l + potasium tellurite 0,01g; boric acid 1,5g and benomyl 0,1g), and TAM (TA - peptone 10,0g, potassium bromide 1,0g, calcium chloride 0,25g agar 15g/1 + Tween 80, 10ml, cephalexin (Ileflex) 40mg, and chlorotalonil (Bravonil 5OPM) 50mg: were more efficient to detect Cm and Xcv, from ground seeds in phosphate buffer than other media evaluated and showed higher specificity and sensitivity than other media, detecting and 103 and 102 cfc.ml-1 of Cm and Xc as compared to 104 and 103 cfc.ml-1 of the inoculation in tomato seedlings (cultivars Angela Gigante and Santa Cruz), respectively. In the case o Cm, the detection of the bacterium in contaminated tomato seed samples, on the semiselective MB1M culture medium, showed reproductibility.