The antimicrobial activities of crude, ethanolic and methanolic extracts of Ocimum basilicum (OB) (Basil plant) against Vibrio cholerae, a bacterial pathogen responsible for cholera were examined in the present study, and their potency, were assessed by agar-streak diffusion method, to ascertain the presence or absence of inhibition zones and zone diameter. Basil leaves (Ocimum basilicum) were peeled off from the standing basil plant. Vibrio species were isolated from borehole and river water using a selective medium, Thiosulphate citrate bile salt agar after pre-enrichment in peptone water and purified in nutrient agar (NA) and used for the assay. NA plates were incubated at 37°C for 24h. Diameter of inhibition zone for sensitive cases was measured. The results showed that the ethanolic extract had slightly higher antibacterial activity compared with methanolic and crude extracts. Two-way analysis of variance indicated that there were significant differences in the zones of inhibitions (ZOI) by V. cholerae using different OBE [F (2,6)=6.404,p<0.05] and from different water sources [F(3,6)=54.763,p<0.05]. There was however no significant interaction in the type of OBE and source of V. cholerae [F (6,23)=0.114, p>0.05]. Also, chloramphenicol had significantly higher antibacterial effect on V. cholerae than the OBE [F(1,6)=108.571, p<0.05]. The range of ZOI reported are comparable to standard references and thus affirm that OBE can be exploited commercially and used to control diarrhoeal illnesses due to enterotoxigenic and enteropathogenic gram-negative bacteria such as Vibrio cholerae.