Flask paraplegic during the infection by the virus of human immunodeficiency (HIV) are very strong and with multiple etiology. The author report a case of flask paraplegic which was the circumstance to discover HIV sero positive with a patient. The aim was to illustrate the difficulties of etiology diagnostic despite the realization of tom densitometry and of medullar IRM. It was a young lady with had 27 years of age who had been admitted for chronic cough, flask paraplegic and a retention of urine. The analysis during her admission notified a flask paraplegic, some sphincterien troubles, without sensibility troubles. There was no signal neither of Babinski nor amyotrophic. The examination of respiratory organ notified a syndrome of pulmonary bilateral condensation. The CT Scan of sacred lamb rachis focused on some discal protrusions of lamb sacred, and the IRM showed an aspect of inflammatory myelite. The pulmonary radio showed interstitial pneumopathy with a right scissurite. The research of some BAAR became negative. The retroviral became HIV positive and the quantity of lymphocytes TCD4 at 118 cellular/ mm3 with a viral charge of 74 782 copies/ ml. The diagnostic of myelite caused by HIV combined to pneumopathy was retained.