In this study, the in-vitro activity of ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole (TMP-SMX), cefoperazone, ceftriaxone, cefotaxime, ceftizoxime, ofloxacin, pefloxacin, ciprofloxacin, and fleroxacin against recently isolated strains of S.typhi (20) and Salmonella group B (42) have been investigated. The minimum inhibitory concentrations (MICs) were determined using the microtube dilution technique except for TMP-SMX which was tested by agar dilution technique. All of S.typhi strains have been found to be susceptible to all antibiotics used in this study. In Salmonella group B bacteria relatively high percentage of resistance has been found against ampicillin (28.6%), chloramphenicol (33%), TMP-SMX (42.9%), cefoperazone (35.7%), and ceftizoxime (12%). All new quinolone derivatives tested were very active against all of the Salmonella strains. The antibiotic therapy proposals on salmonellosis in adults have been discussed in the light of our results, our clinical experience and the other studies.