A fatal case of primary amoebic encephalitis (PAM) in a 20 year old boy, a proven case of acute leukemic leukemia (ALL) type L2, in remission is described. No history of swimming could be elicited. The clinical presentation, the isolation of the amoeba from the cerebrospinal fluid (CSF), the poor response to amphotericin B, and the ultimately fatal outcome are all consistent with the diagnosis of PAM. On the basis of its ability to grow at temperature 42ºC and 45 ºC, morphology of trophozoite, and the presence of flagellate forms in CSF, the amoeba was identified as Naegleria fowleri. Other drugs used in combination with amphotericin B are tetracycline, rifampicin, and miconazole. A possibility of PAM should always be considered in all cases of acute purulent meningoencephalitis in which no bacteria or fungus are found. Key-Words: Naegleria, meningoencephalitis, fatal.Primary amoebic meningoencephalitis (PAM) is a fulminant, often rapidly fatal infection affecting individuals with a recent history of swimming in warm water. It is caused by a free living amoeba Naegleria fowleri, an organism ubiquitous in soil and fresh water habitats [1]. It was first described by Fowler and Carter from Southern Australia in 1965, who found these in four autopsied patients [2]. The disease appears to be uniformly fatal and at present there is no standard regimen of therapy. Amphotericin B, tetracycline, rifampicin, and miconazole have been reported to have in vitro growth-inhibitory activity against this organism [3,4]. Approximately 310 cases of PAM have been reported internationally, mostly from United States, Australia and Europe. There are only seven survivors of PAM reported in Western Literature [5][6][7][8][9][10][11]. From India, only two survivors of Naegleria meningitis have been reported so far [12,13]. Case ReportA 20 year old male was admitted to a tertiary care institute in North India with history of fever, headache, loss of vision, hearing loss, slurring of speech, difficulty in swallowing and retention of urine for two days. All the relevant history of tuberculosis, diabetes mellitus and hypertension was insignificant. Prior to this illness he was a proven case of acute leukemic leukemia (ALL) type L2. He was put on standard chemotherapy consisting of adriamycin, vincristine, methotrexate and prednisolone and palliative; external radiotherapy to cranium, chest and neck on account of supraclavicular lymphadenopathy and mediastinal mass. The patient was under close follow-up and went in remission phase (proved by bone marrow aspiration) and was put on maintenance therapy.Examination on admission revealed a young boy with a markedly stiff neck and a temperature of 38.5 ºC. He was oriented, responded to painful stimuli and the limbs were hypertonic but no focal neurological signs were present.Ophthalmological examination revealed keratitis, mild glaucomatous cupping, early papilloedema and left lateral rectus palsy. The CT scan head showed no abnormality.Laboratory studies showed hemoglobin of 9 g/dL, hematocrit 39%...