Fifty-five strains of Helicobacterpylori isolated from November 1997 until October 1998 from 33 female and 22 male adults attending for endoscopy at the Evangel Hospital, Jos, Nigeria were assayed for antibiotic susceptibility to amoxycillin, clarithromycin, metronidazole and tetracycline by the E-test strip method. Minimum inhibitory concentration (MIC) within the attainable peak serum concentrations for each drug was used as the parameter to determine the susceptibility of H. pylori. The results showed 100% susceptibility for amoxycillin, 89.0% for tetracycline, 87.3% for clarithromycin and 60% for metronidazole. The MIC,, and MICgO values were: 0.016 pg/mL and 0.75 pg/mL for amoxycillin, 0.016 pg/mL and 2 pg/mL for clarithromycin, 0,094 pg/mL and 12 pg/mL for tetracycline, and 2 pg/mL and > 48 pg/mL for metronidazole. The MICgo values for metronidazole (> 48 yg/mL) and tetracycline (12 pg/mL) were in each case higher than the break-point value (peak serum concentrations) of 8 pg/mL for metronidazole and 3 Fg/mL for tetracycline. This pattern of resistance to metronidazole and tetracycline has to be considered when therapeutic regimens against H. pylori contain either or both drugs.