Abstract: The effects of period of fermentation on the chemical composition and selected functional properties of millet (Pennisetum americanum) and Pigeon pea (Cajanus cajan) seed flours were examined. The fermentation time ranged from 24-96 h. Flours of the unfermented seeds served as controls. Fermentation for 24 h decreased (p<0.05) crude protein in both millet and pigeon pea flours. At 72 h, significant increase (p<0.05) in crude protein occurred in pigeon pea. Ether extract and metabolizable energy increased (p<0.05) in both flours at 72 h fermentation. Apparent decreases (p>0.05) occurred in the total ash of both flours with increase in fermentation time except at the 96 h of pigeon pea. Tannin level was lowest in both flours at 72 h. Significant (p<0.05) decreases in cyanide occurred in pigeon pea from the 24 h and was lowest at the 72 h. Phytate was low in both flours. A 10% (w/v) gruel of millet and pigeon pea flour exhibited 363 cp and 380 cp apparent viscosity respectively at 72 h fermentation. Significant (p<0.05) reduction in water absorption capacity occurred only at the early stages (24 and 48 h) of fermentation in millet. Water Solubility Index increased in both flours with increase in fermentation period while reconstitution time reduced significantly (p<0.05). Least gelation concentration increased by 100% in pigeon pea at 48 h and 72 h. Fermenting for 72 h seem to offer some advantages over other periods.