The toxin (BOAA, beta-N3 oxalylamino-L-alanine) contents of Lathyrus sativus (khesari) grown in different regions of Bangladesh (from Chittagong to Dinajpur and from Sylhet to Khulna) were measured by a standardized calorimetric method. The major varieties grown in Barisal, Charbadna, Jamalpur and Pahartali contained 486, 837, 540 and 527 mg BOAA per 100 g dried seed. Other values ranged from 552 mg/100 g at Bola and 570 mg/100 g at Khulna to 905 mg/100 g at Dinajpur and 973 mg/100 g at Rangpur. However, in Faridpur, the neighbouring district of Barisal or Khulna, the seed had a rather high value of 848 mg/100 g; on the other hand, in the Northern district of Bogra, which is near to Rangpur, the BOAA content was only 628 mg/100 g. In Rajshahi and Kushtia (regions known as the lathyrism pocket), the BOAA contents were 686 and 636 mg/100 g, respectively, values intermediate between those observed in seeds grown in Bola and Khulna, or Rangpur and Dinajpur. The data thus indicate that there is no clear-cut correlation between BOAA content of seeds grown in different regions of Bangladesh, nor does there exist any positive correlation between toxin content of Lathyrus seeds and the prevalence of lathyrism.