ABSTRACT. An actual clinical case of the diagnosis and course features of non-tuberculosis mycobacterial infection (NTMI) of the lungs and larynx in a patient treated at the Zaporizhzhia Regional Phthisiopulmonology Clinical Treatment and Diagnostic Center is presented. The clinical case demonstrates the difficulty of differential diagnosis of NTMI of the lung caused by scotochromogenic mycobacterium and tuberculosis, since the clinical and radiological manifestations for both diseases are identical, and there are no pathognomonic symptoms of NTMI. NTM affect the respiratory system and mimic the symptoms of tuberculosis, which significantly complicates not only timely differential diagnosis, but also leads to “treatment failure” of tuberculosis, which the patient did not have. After a month of antimycobacterial treatment an ulcerative lesion of the right vocal fold was diagnosed in the patient. Detection of the culture of NTM 1.5 months after its inoculation was the only one method of diagnosis in this case, the diagnosis NTMI of both the lungs and the larynx was made considering those results. The patient did not receive appropriate treatment before receiving the results of the bacteriological examination, which led to the development of negative clinical and radiological dynamics. But, despite the late diagnosis of NTMI, after 6 months of appropriate treatment the patient had a positive clinical and X-ray dynamics with healing of the ulcerative lesion of the right vocal fold. Thus, the presented case shows that despite the late diagnosis of NTMI of the lungs, which was complicated by NTMI of the larynx during antimycobacterial therapy, in the absence of severe concomitant lung diseases in the patient, after 6 months of appropriate treatment of NTMI, it was possible to achieve positive clinical and radiological dynamics with complete healing of the ulcerative lesion of the right vocal fold.