Abstract: A large proportion of the population in Africa still relies on the use of herbal remedies, which have been claimed to produce beneficial responses. Lagenaria breviflora is one of those numerous plants used as antibacterial and antiviral herbal remedies in local communities in Nigeria. In this study, the efficacy of ethanolic extract of whole fruit of Lagenaria breviflora against common bacteria species such as B. subtilis, S. aureus, S. gallinarium, P. aeruginosa, Klebsiella sp., Proteus sp. and E. coli was investigated. Antibacterial activity was determined by agar-well diffusion method and expressed as the average diameter of the zone of inhibition of bacterial growth around the wells. The effect of the extract was compared with that of the two standard antibiotics (ofloxacin and erythromycin) used. The difference of the means was considered significant at p< 0.05 using Student t-test. The extract potently inhibited the growth of all the bacterial colonies studied. This inhibitory effect was also dose dependent. The antibacterial effect of L. breviflora has a broad spectrum activity because it inhibited the growth of colonies of Gram positive bacteria (B. subtilis and S. aureus) and that of Gram negative bacteria (S. gallinarium, P. aeruginosa, Klebsiella, Proteus and E. coli). Compared with standard antibiotics, the extract had moderate activity. While ofloxacin was observed to be significantly (p< 0.05) more potent than the extract for all the bacteria species studied, the extract was itself more potent than erythromycin on all the bacteria species; P. aeruginosa, S. aureus and Proteus sp were not even sensitive to erythromycin at all in this study. The degree of inhibition by the plant extract varies from one bacteria colony to the other. The bacteria colonies were susceptible to the antibacterial activity of the extract of L. breviflora in the following descending order; B. subtilis> S. gallinarium> S. aureus> P. aeruginosa> Klebsiella=Proteus> E. coli Findings from this study show that the ethnomedical use of the plant as antibacterial remedy is well placed and further effort is warranted; in order to isolate and elucidate the active principles in the plant with the view of deriving the potential therapeutic benefits inherent in L. breviflora.