Studies were conducted on the antibacterial efficacy of water and ethanolic extracts of cinchona bark on the activities of some selected bacterial species which include: Escherichia coli (E. coli), Pseudomonas aeruginosa, Streptococcus faecalis, Staphylococcus aureus and Bacillus subtilis. These bioassays were carried out using pour plate, disc and agar ditch techniques. Phytochemical studies of the extracts revealed that saponins, flavonoids, tannins, anthocyanins, phlobatannins were present, whereas betacyanins were absent. The observed zones of inhibition produced by the water and ethanol extracts showed that the water extract was more efficacious than the ethanol extract. The ethanol extract on the other hand, became more active on application of heat at 121 ^oC. This increase in activity could be due to the effect of concentration of the biologically active constituents of the bark extract. The antibacterial activities of the plant extracts suggest that they could serve as broad   spectrum antimicrobial agents.