Two hundred and ten, day old straight run coloured chicken (Chabro) were randomly distributed into seven dietary treatments:T1-basal diet, T2-T1+0.25% Mint leaf meal (MLM), T3- T1+0.5% MLM, T4- T1+0.75% MLM, T5- T1+1% MLM, T6-T1+1.25% MLM, T7- T1+1.5% MLM, having three replicates each. During 4-8 weeks, T4 birds had significantly higher (P<0.01) body weight gain and significantly better (P<0.01) FCR than T3, T5, T6 and comparatively better performance than T1. HA response to 1% SRBC (log2 titre) and cell mediated response to PHA-P was significantly higher (P<0.01) in T4. Percent ether extract of breast and thigh muscle was significantly lower (P<0.01) in T6 than T1. Thus, dietary supplementation of 0.75% mint leaf meal resulted in significantly higher humoral and cell mediated immune response in coloured chicken. Further, dietary supplementation of 1.25% mint leaf meal resulted in decrease in percent crude fat of breast and thigh meat cuts in coloured chicken.