In the traditional system of medicine, medicinal plants form the back-bone in India. The photochemical ingredients from these medicinal plants serve as key compounds in drug discovery and design. A diverse range of bio active molecules are produced by plants which make them a rich source of different types of medicines. Aegle marmelos is commonly known as Bilva tree belong to family Rutaceae. This plant is considered as a medicinal tree as it has several curative properties in treating different diseases. The seasonal variation of total ash, acid soluble ash and acid insoluble ash have been investigated from leaves, wood, bark and root of Aegle marmelos, which are medicinally important. Comparative account of total ash, acid soluble ash and acid insoluble ash content of bark showed high level of total ash in summer season (14.900%) and low level of total ash content in root during monsoon season (6.700%). The water soluble ash showed higher level in bark during summer (5.475%) and lower in root of monsoon (2.100%). Comparative account of water insoluble ash in leaves showed higher (11.125%) in monsoon and lower in the root during monsoon (4.600%) as compared to other seasons.