Necrotizing otitis externa, also known as malignant type of the inflammatory process, represents an infection of the skin of external hearing canal, a fast development of tissue necrosis and infection spreading to the surrounding structures. Basic clinical characteristics are: strong earache, leaking from ear, granulation findings at the bottom of the hearing canal, the disorder of hearing function and a potential possibility of complications (paralysis of facial nerve, intracranial infections). Mycrobiologically the most present bacerium is Pseudomonas aeruginosa. Other microorganisms that can be isolated are Aspergillus species, Staphylococcus aureus, Proteus mirabilis, Klebsiella oxytoca, Candida parapsilosis. The disease is more common in patients with general diseases, mostly of metabolic nature (diabetes mellitus). The approach to diagnosis and therapy is usually urgent in order to prevent the development of serious complications. This paper shows the results of the analysis of clinical process of malignant otitis in 25 patients from the Clinic of ORL and MFS KCS according to the type of the cause and the development of potentially severe and life threatening complications.