The cardiovascular drug nifedipine exhibited significant in vitro and in vivo antibacterialactivity against 331 strains of bacteria belonging to three Gram-positive and twelve Gram-negative genera. The minimum inhibitory concentration of the drug, as determined both byagar and broth dilution methods, was seen to range from 25 - 200 µg/ml against most testbacteria, including several pathogenic ones, in the in vitro studies. Nifedipine was bacteriostaticin action. In vivo studies with this drug showed that it could offer statistically significantprotection (P < 0.001) to mice challenged with a virulent bacterium. Therefore, nifedipine hasthe potential of an antibacterial agent, which may be developed after further pharmacologicalstudies.