A range of bacteria were screened to identify potential antagonists againstBotrytis cinereaon grape tissue (Vitis viniferaL.). From dual culture tests, 13 isolates were selected which exhibited antagonism towardsB. cinereamycelial growth. Inhibition zones ranged between 3 and 12 mm. These isolates were screened in a grape leaf bioassay. Irradiated leaf discs were inoculated with5. cinerea(1 × 104spores/ml) then challenged with bacteria applied at 1 × 108colony forming units (cfu)/ml in tryptic soya broth (TSB). Sporulation ofB. cinereawas significantly (P =0.05) reduced on leaf discs treated withSerratia liquefaciensisolates B47 and 171B by 62 and 57% respectively, 7 days after application. In a second leaf bioassay, B47 applied in TSB significantly (P =0.05) reducedB. cinereasporulation by 65% after 21 days compared to a 39% suppression achieved with isolate 171B (applied in TSB) and the fungicide, iprodione. However, when applied in Ringers solution, both isolates failed to reduceB. cinereasporulation. This research has identified two isolates ofS. liquefaciensable to suppress sporulation ofB. cinereaon grape tissue and has shown that bacterial application solution can strongly influence the degree of suppression achieved.