During 1981-83, 12 to 16 years old jack fruit (Artocarpus heterophyllus L.) trees grown in Chittagong University campus were severely affected with brown leaf spots. Nigrospora sphaerica (Sacc.) Mason and Pestalotiopsis Versicolor (Sperg.) Steyaert were found to be associated with the disease (Herb. IMI No. 266275) and the pathogens are a new record for the plant. As these fungi have not been reported on jack fruit tree in Bangladesh, a study was made to determine their pathogenicity with jack fruit plant. The disease samples were collected and the symptoms of the disease were recorded carefully. The most characteristic symptoms of the disease appeared in the months of December, January and February. At first brown yellow coloured spots of 0.5-10mm. appeared on infected leaf and then the spots gradually coalesced and became larger to attain a size upto 11.0 cm.