Abstract: OBJECTIVE:: Malignant external otitis (MEO) continues to pose a diagnostic and therapeutic challenge. The lack of a diagnostic study since 1987 combined with recent findings of quinolone-resistant MEO prompted the present analysis of MEO outcome in a major tertiary medical center. METHODS:: Seventy-five consecutive patients hospitalized for suspected MEO between 1990 and 2003 were divided into 2 diagnostic groups: MEO Type 1, presence of all obligatory clinical and radiologic criteria and most of the occasional criteria of Cohen and Friedman or absence of 1 obligatory criterion with failure of intensive treatment, and MEO Type 2, absence of one of the obligatory criteria with treatment response within 1 week. The groups were compared for demographic data, underlying diseases, ear parameters, culture findings, length of hospitalization, and treatment before hospitalization, obtained from the charts. RESULTS:: Both types of MEO affected mostly diabetic patients and were characterized by granulations and discharge in the external ear, severe prolonged pain, soft tissue involvement and bone destruction on computed tomographic scan, and growth of Pseudomonas aeruginosa in culture. However, Type 1 MEO was associated with a significantly older patient age at presentation, higher rate of oral antidiabetic treatment, history of diabetic (vascular) complications, computed tomographic findings of nasopharyngeal involvement (soft tissue swelling, soft tissue asymmetry, or abscess formation), bone destruction, and temporomandibular joint involvement-all of which led to significantly longer treatment and shorter survival. CONCLUSION:: The worse prognosis of Type 1 MEO compared with Type 2 should alert clinicians to establish earlier diagnosis and treatment.