Sugar beet affected by soft rot bacteria and causes great loses in yield. Organic acids are known for their antibacterial and antifungal properties. Three strains of soft rot bacteria, Erwinia carotovora subsp. carotovora (Ecc), Erwinia carotovora subsp. betavasculorum (Ecb) and Burkholderia cepacia (Bc) were treated with acetic, ascorbic and citric acids  with concentrations (1.0, 2.5 and 5%) and control was used SDW and antibiotic (Streptomycin 0.015%). The (MIC)of acetic acid for Ecc, Ecb and Bc was determined at concentrations ranging (0.25, 0.35, 0.50, 0.75, 0.80 and 0.90 % V/V); controls were maintained with sterilized water and antibiotic (Streptomycin 0.015%). Determination of inhibitory effect to acetic acid on Ecc by culturing it in NA broth medium to mid-log phase and bacterial suspension (10⁸cfu/ml) was prepared. The cell suspension was incubated at 37^oC for 60 min with acetic acid at a concentration of MIC (0.90 %) then observed using a scanning electron microscope.  The organic acid, acetic acid,  had  highest  efficacy  in inhibiting  the  growth  of  Ecc, Ecb and Bc  at concentration 5% with  inhibition  zone  23  mm. The MIC of acetic acid on Ecc, Ecb  and  Bc  was 0.90 %V/V showed the highest antibacterial activity against bacterial strains, while concentrate 0.25% revealed the lowest inhibitory effect. The cells treated with acetic acid became swell and enlarged in size then explode and smallest, surface roughening and corrugating compared with the control.