Mango is a popular fruit having some special organoleptic features such as excellent flavor, pleasant aroma and taste. Healthy and disease free seedlings are of prime need and basic raw material for establishment of orchards and production of mango. But seedling diseases are one of the important problems in the tropics. Occurrence and prevalence of diseases of mango was studied at Dhaka and Manikgonj in Bangladesh in 2007. Altogether six diseases were recorded during the survey. The diseases, in order of prevalence (incidence and severity) were Anthracnose (51.14% and 37.39%), Alternaria leaf spot (47.14% and 32.55%), Powdery mildew (33.30% and 26.03%), Red rust (24.05% and 13.05%), Sooty mould (10.50% and 10.95%) and Bacterial leaf spot (9.75% and 10.12%). The highest prevalence of Anthracnose and Alternaria leaf spot was observed in October and lowest in January. The highest prevalence of Red rust and Powdery mildew was in the month of March, but the disease was observed in October. Report on Alternaria leaf spot first of its kind in mango seedling in the country. This book may be useful to plant patholoogists, student, teachers and any one inteested in this field.