Biochemical changes in the flour of two untreated maize varieties viz. 'Vijay-normal' and 'Shakti-opaque-2' stored for 180 days, were studied under ambient conditions. Oil content of 'Vijay-normal' and 'Shakti-opaque-2' flours were 4.6 and 5.1 per cent respectively. Fatty acid composition in both the varieties almost remained constant during storage. Increase in peroxide and acid values during storage, ranged from 6.1 to 7.3 and 1.0 to 55.9 per cent in 'Vijay-normal' and 7.2 to 8.2 and 0.5 to 51.5 per cent in 'Shakti-opaque-2' respectively. Bacterial count in 'Shakti-opaque-2' flour decreased whereas that of fungal infestation increased after 180 days of storage. Acid value in flour prepared after heat treatment of kernels (80-degrees-C, 3 hr) was almost constant during 30 days of storage.