The cases of three patients aged over sixty, diabetic for a long time and having clinical, otological, neurological and microbiological findings of malignant external otitis by Pseudomonas aeruginosa are registered. The first patient, a 62 years old woman, had important neurological alterations, such as proven P. aeruginosa meningitis and involvement of the 6th, 7th, 8th, 9th and 10th left cranial nerves. Although mortality and morbidity rates of cases with these characteristics are reported to be high, this patient survived. The second was a 64 years old male with the classical complaints of this condition consisting of persistent and intensive ear pain, serous purulent discharge and an emerging tumourous lesion in the left external ear canal. Good results were obtained with the surgical treatment administered along with an antimicrobian plan which remained uncompleted because the patient has requested his discharge from the hospital. In less than one month, he was again hospitalized already presenting neurological manifestations (paralysis of the 6th cranial nerve) following a fatal course in a few days. The third was also a male patient, 70 years old, whose inicial complaints occurred after a month a butterfly penetrated his right ear during his sleep. In spite of the presence of neurological.troubles (facial paralysis and stupor) he survived with a prolonged antibiotic therapy. After a literature revision on this pathology, considerations are made concerning its pathogeny, clinical findings, diagnosis, therapy and prognosis.