E-test was employed to detect the in-vitro efficacy of various antibiotics against H. influenzae (n=25), M. catarrhalis (n=26), S. pneumoniae (n=44) and S. pyogenes (n=56). Results were evaluated according to the NCCLS criteria. In-vitro resistance to ampicillin was 8% in H. influenzae and 77% in M. catarrhalis, but there was no resistance to amoxycillin clavulanic acid in either organisms. None of the isolates were resistant to cefaclor and cefotaxime. There was 2% sparfloxacin and 14% ciprofloxacin resistance in S. pneumoniae. Resistance to erythromycin was 100% in H. influenzae, 8% in M. catarrhalis, 4.5% in S. pneumoniae and 2% in S. pyogenes. According to these results all the agents tested except ampicillin, erythromycin and ciprofloxacin can be used in the empirical treatment of infections suspected to be due to these organisms, however, susceptibility tests are required after the causative agent is detected.