Objective: Although Moraxella species are members of the normal respiratory flora, some species, including M. catarrhalis, M. osloensis, M. nonliquefaciens, and M. lacunata, can cause serious infections in humans. The purpose of this study was to investigate the antimicrobial susceptibility of Moraxella species other than M. catarrhalis. Material and Methods: The study included 17 M. osloensis, 18 M. lincolnii, and three M. nonliquefacie, isolated from 100 nasopharyngeal samples. The isolates were identified by conventional methods. Identification to the species level was performed by a RapID NF Plus identification kit (Remel, USA). The antimicrobial susceptibility of the isolates was examined for ampicillin, amoxicillin/clavulanic acid, gentamicin, ceftazidime, ciprofloxacin, erythromycin and trimethoprim-sulfamethoxazole using the disk diffusion method. The results were evaluated according to guideline published by the Clinical and Laboratory Standards Institute. ß-Lactamase production was tested using nitrocefin discs. Results: The resistance rates of isolates were between 3% and 8% for trimethoprim-sulfamethoxazole, amoxicillin/clavulanic acid. Inhibition zone diameters for ampicillin of 41% of M. osloensis, 33% of M. nonliquefaciens, and 11% of M. lincolnii isolates were relatively small (?15 mm). Five M. osloensis (29%) and one M. nonliquefaciens, isolates were beta lactase positive. Conclusion: Moraxella species other than M. catarrhalis can cause serious infections in humans. Therefore, we suggest that Moraxella species other than M. catarrhalis should be included in surveillance studies. © 2015 by Türkiye Klinikleri.