Owing to the frequent occurrence in tropical countries of subacute spinal cord diseases of unknown origin, a nosological entity called tropical spastic paraparesis has been individualized. Twenty-two cases have been observed in Martinique. The presence in the serum of antibodies directed against human T-cell leukaemia/lymphoma virus (HTLV-I) in 15 of these 22 patients suggests that this lymphotropic virus or a related one might also be neurovirulent.