Bacterial canker disease is one of the most economically destructive diseases of tomato (Solanum lycopersicum) caused by gram positive bacterium, Clavibacter michiganensis Different disease controlling mechanisms have been employed to tackle the problem. These days using plant extracts is a new research focus area to reduce the side effect of chemical pesticides. The current study is aimed to evaluate antibacterial potential of some medicinal plants against Clavibacter michiganensis. The methanol and aqueous extracts of five medicinal plants namely Vernonia amygdalina, Adhatoda shimperiana, Calpurnia aurea, Ricinus cummunis and Moringa oleifera were evaluated in vitro using disc diffusion method. The fresh leaves of plants were dried at room temperature under shade and ground to fine powder. Extraction was carried out using maceration method and the phytochemical composition of extracts was analyzed qualitatively. Clavibacter michiganensis was isolated using yeast dextrose calcium carbonate agar (YDC) medium from infected tomato fruits collected and identified by colony morphology and pathogenicity test. The higher extract yield was obtained from C. aurea (21.5%). Alkaloids, flavonoids, phenols, terpinoid, saponin and tannins were found from the tested extracts. All the tested extracts showed antibacterial activity against Clavibacter michiganensis with significantly different inhibition zone diameter. The highest antibacterial activity and relative percentage inhibition was showed by extracts of R. cummunis followed by V. amygdalina and Moringa oleifera in both solvent extracts. Extracts of R. cummunis and V. amygdalina showed the lowest MIC value (3.15mg/ml and 6.25mg/ml respectively). A. schimperiana and R. communis showed bactericidal effect against C. michiganensis while M. oleifera and aqueous extract of V. amygdalina showed bacteriostatic effect. The extracts of R. communis, V. amygdalina and M.oleifera could be candidates for further development as biocides in the control of tomato canker disease. However, further studies should be done to evaluate their performance under field conditions. Key words: Aqueous extract, Clavibacter michiganensis, Inhibition zone, Medicinal plants, Methanol extract, Tomato