Neurolathyrism is a form of human spastic paraparesis related to the overconsumption of the legume Lathyrus sativus or grass pea (Khesari in Bangladesh) containing the neurotoxin 3-N-oxalyl-2,3-diaminopropanoic acid (beta-ODAP). The clinical symptoms of neurolathyrism are similar to those of Tropical Spastic Paraparesis. In order to eliminate the proposed causative agent of TSP (HTLV-I) as a potential cause of the symptoms ascribed to neurolathyrism, a total of 444 diagnosed lathyrism patients were screened for HTLV-I antibodies. 50 CSF and 394 serum samples were collected from male (415) and female (29) patients. Only 4 serum samples were found sero-positive for HTLV-I. This agrees with the assumption that overconsumption of beta-ODAP containing Lathyrus seeds, and not HTLV infection, is the causative agent for neurolathyrism.