Injera is a widely consumed staple fermented food in Ethiopia and is mostly made from teff. Most communities in Ethiopia like to consume teff injera but due to the high price of teff, only middle and high-income people can afford it. Due to this blending other cheapest cereals with teff is very important. Therefore, this study was conducted to investigate the effect of blending ratio and fermentation time on the physicochemical, microbiological, and sensory qualities of injera. The treatments consisted of five blends ( BR1 40% pearl millet, 55% teff, and 5% buckwheat, BR2 30% pearl millet, 60% teff, and 10% buckwheat, BR3 20% pearl millet, 65% teff, and 15% buckwheat, BR4 10% pearl millet, 70% teff, and 20% buckwheat) and 100% teff) and three fermentation times (36, 72, and 108 h). The experiment was laid out as a completely randomized design in factorial arrangements (5x3=15 treatments) with triplication. The physicochemical, Microbiological, functional, and sensory qualities of flours and injera samples were analyzed using standard methods. The nutritional composition of composite flour varied from 8.58-9.94% (protein), 3.70-5.0% (fat), and 2.28-2.62% (fiber), 71.88-74.90% (carbohydrate), 8.64-11.12 mg/100g (iron), 72.82-93.14 mg/100g (calcium) and 1.32-1.74 mg /100 g (zinc). The anti-nutritional content of composite flour ranged from 458.39-487.94 mg/100g (phytic acid) and 28.25-40.27 mg catechin eq. /100g (tannins). The nutritional composition of injera ranged from 9.06-11.82% (protein), 2.60-5.10% (crude fat), 1.97-2.56% (crude fiber), 1.78-2.24% (total ash), 71.43-75.34% (carbohydrate), 364.99-375.29 kcal/100g (energy), 9.56-12.82 mg/100g (iron), 82.28-136.22 mg/100g (calcium), and 1.14-3.32 mg/100g (zinc). Injera made from BR1 fermented at 108, and 36h were showed the highest crude protein (11.82%) and energy (375.29 kcal/100g), respectively but the highest crude fiber (2.56%) obtained from BR4 fermented at 36h and the highest total ash and carbohydrate were observed in the control injera fermented at 36h. The phytic acid and tannin content of injera ranged 89.56-221.07 mg/100g and 5.90-19.23 mg catechin eq/100g, respectively. Sensory acceptability of all injera scored above the average mean rating which is an indication of the goodness of the products. The most preferred injera by the panelist was produced from 20% pearl millet, 65% teff, and 15% buckwheat flour fermented for 72h. The microbial load of injera ranged from 2.45-3.92 log cfu/g and 5.78-7.75 log cfu/g (aerobic plate count), 2.82-3.98 log cfu/g, and 6.40-7.94 log cfu/g (yeast and mold) for the 3 rd and 6 th day’s storage, respectively. Generally, this study concluded that up to 30% pearl millet, 20% buckwheat blending, and 72h fermentation could be recommended in the preparation of nutritionally improved injera and it could be used as a substitution of teff injera. Keyword: Blending ratio, Buckwheat, Composite flour, Fermentation time, Injera, Nutritional quality, Pearl millet, Sensory acceptability