ABSTRACT An investigation into the replacement value of tiger nut seed meal as substitute for maize in diets of Japanese quail was studied. Four different diets were formulated such that tiger nut replaced maize at 0% (T;), 25% (T»), 50% (Ts) and 75% (Ta) respectively in a Completely Randomized Design. The control diet (T) contained no tiger nut. One hundred and twenty day-old Japanese quails procured from the University Teaching and Research farm was used for the experiment to determine the effect of the test diets on dietary proximate compositions, feed intake, weight gain, body weight changes, Feed Conversion Ratio, carcass cut parts and organ proportions in a 49- days trial. The quail chicks were arranged into the 4 dietary treatments, each containing 3 replicates with 30 birds per dietary treatment and 10 birds per replicate. Result indicated that the control diet did not vary from the test diets in proximate composition. The crude fat, crude fiber and metabolizable energy portrayed an increasing trend whereas, the crude protein, ash and nitrogen free extract portrayed a decreasing trend as the level of tiger nut increased. Significant differences were observed in the weekly values of daily feed intake, daily weight gain, body weight changes and Feed Conversion Ratios of the dietary treatments. However, based on average values, the average daily intake, average body weight changes and average Feed Conversion Ratio did not vary among the dietary treatments, which suggest that tiger nut did not produce adverse effect up to the 75% levels. Average body weight changes increased (97.90 g - 114.17 g) as the level of tiger nut increased, from the 25% level up to the 50% (Ts) and declined thereafter. T» recorded the lowest FCR value (5.96) which portrays it as the best in terms of feed conversion to lean meat. T; recorded the highest FCR value though (6.88) which implies that the diets containing tiger nut improved FCR but, optimally at 50% level. The average daily weight gain however, portrayed significant differences, wherein, T3 recorded the highest value (4.28 g/day), whereas, T; recorded the least value (3.34 g/day). This indicates that tiger nut depresses weight gain at 75% level of inclusion. The result of the carcass cut parts showed that body liveweight, drumstick, thigh, shank, wings, head size and anus varied due to the influence of the dietary treatments, whereas, dressed weight, back, breast and neck were not affected by the diets. Drumstick and anal weights were reduced, whereas, thigh and head size increased with an increase in the level of tiger nut. Age, sex, alkali treatment of tiger nut and climate are factors that probably affected the result of this study. The interaction of energy and protein levels of the diets did not affect dressed weight contrary to some previous findings. T, performed better in shank length (1.81%) and dressed weight (84.92%). Ts was moderate in most performances. Ta was least in shank (1.59%) and wing weights (6.99%). The organ proportions was influenced by the diets in liver/spleen, gizzard and intestinal weights, but showed no influence in kidney, heart and proventriculus weights. The dressed percent was highest in T, (84.92%). The liver weight was most significant in T, (3.50 % lwt). Gizzard size was highest in T; (4.67%) compared to the control (3.27%) and increases with high fiber diet. The gizzard and liver weights variation were attributed to the differences in the influence of dietary energy and protein interaction as well as fiber digestibility. The high value of the liver in T, favoured the internal organs. Based on the feed conversion ratio and daily weight gain, the 50% level (T3) is recommended but based on carcass cut parts and organ proportions, the 25 % level of inclusion of tiger nut is recommended for replacing maize. Further research should attempt levels between 25 and 50 % tiger nut inclusion, and equally consider partitioning gender, energy and protein levels for more precise results. Treating the raw tiger nut in order to attenuate the possible effects of anti-nutrients is also recommended. In conclusion,tigemut can replace maize at levels that ranges at 25%