Abstract: Investigations were carried out on the growth and production of polygalacturonase of Aspergillus flavus isolated from cropped soils on different raw and commercial carbon substrates. All the carbon substrates supported the growth and production of polygalacturonase of the fungus in varying proportion. The pattern of growth was ripe banana peel> orange bagasse> unripe plantain peel> potato peel> unripe banana peel> ripe plantain peel> soluble starch> cassava peel> control. Potato peel supported the highest polygalacturonase production followed by ripe banana peel, then orange bagasse, ripe plantain peel, unripe plantain peel, soluble starch, sucrose, unripe banana and cassava peel, while the control had the least. The raw carbon substrates supported the growth and polygalacturonase production more than the commercial carbon substrates and control. The pH of the culture filtrates ranged from 6.20 to 6.62. Proximate composition of the raw carbon substrates shows the presence of ash, moisture, protein, crude fibre, fat and carbohydrates in varying proportion. Mineral analysis shows the raw substrates contained essential elements namely Na+, K+, Ca2+, Mg2+, Fe2+ and Mn2+. Polygalacturonase could be considered as constitutive and inducible enzyme in Aspergillus flavus. Also, the raw carbon substrates contained required nutrients for growth and polygalacturonase production, hence could be used for the growth of Aspergillus flavus for an inexpensive production of polygalacturonase for industrial applications.