Introduction: Nocardia spp. are gram-positive bacteria from the aerobic Actinomycelates family with low level acid resistance, in thinfilamentous structure, branches out in bead shapes. The mechanisms of pathogenesis are complex, not fully understood, and include thecapacity to evade or neutralize the myriad microbicidal activities of the host. Nocardia spp. have the ability to cause localized or systemicsuppurative disease in humans and animals. Nocardiosis is typically regarded an opportunistic infection, but approximately one-third ofthe infected patients are immunocompetent. In this study, patients in whom Nocardia spp. had been isolated were clinically evaluatedin terms of underlying illnesses, laboratory findings and response to therapy.Materials and Methods: Cases whose microbiologic samples yielded Nocardia spp. as the cause of infection between the years 2008and 2015 were evaluated retrospectively via the analysis of hospital records.Results: A total of 16 cases whose microbiologic cultures yielded Nocardia spp. (4 females, 12 males; mean age 52.5 ± 18.0 years;range 19-76) were included into the study. Thirteen patients presented with lung involvement, whereas one had dermal nocardiosis,one had osteomyelitis and one had cranial abscess. Clinical samples that yielded Nocardia spp. included sputum (n= 7), bronchialaspiration sample (n= 3), deep tracheal aspiration (n= 2), tissue biopsy culture (n= 2), abscess material (n= 1) and bronchoalveolarlavage fluid (n=1). Underlying diseases were malignity (n= 4), chronic obstructive pulmonary disease (n= 2), systemic connectivetissue disease (n= 3), interstitial lung disease (n= 2), heart transplantation (n= 1), cirrhosis (n= 1), Cushing disease (n= 1), Downsyndrome (n= 1), and Fahr’s syndrome (n= 1). Fever, cough and sputum were the most common symptoms. Eight patients hadconsolidation in the thorax computer tomography, ten patients had high CRP, seven patients had leukocytosis, and ten patients hadhigh erythrocyte sedimentation rate. Eight of the patients were treated with trimethoprim sulfamethoxazole, two with carbapenem,one with a combination of trimethoprim sulfamethoxazole and imipenem, one with imipenem and linezolid, one with piperacillintazobactam, and one with clarithromycin. One patient with heart transplantation died at the time of microbiological diagnosis andone patient died due to aspergillus infection.Conclusion: It is important that Nocardia spp. can cause opportunistic infections particularly in immunosuppressed patients. Since thebacteria may grow in 2-7 days in clinical samples, incubation time must be prolonged for not to be unnoticed and early treatment mustbe started. It must be kept in mind that within the case of late treatment, the disease may cause mortality.