An experiment was conducted to evaluate the growth performance and cost per gain of Brahman  local crossbred bull calves receiving three diets with varying concentrate to roughage ratio (C:R) of 75:25, 65:35 and 55:45 on dry matter (DM) basis. Twelve bull calves (aging 11.5 ± 1.2 months and 170.8 ± 13.0 kg live weight) divided into three equal groups were fed on three diets. The diets were balanced to 14.5% crude protein (CP) level and 10.5 MJ metabolizable energy (ME) per kg DM, formulating different concentrate mixtures. German grass (Echinoclora grousgali) and paddy straw were offered at 2:1 ratio on DM basis as roughages. The results revealed that C:R ratio did not affect (P > 0.05) the intake of feed and nutrients, feed efficiency (7.04, 6.94 and 6.76) and average daily gain (981, 958 and 976 g). Digestibility of nutrients was not affected (P > 0.05) by C:R. Animals fed diet with C:R = 55:45 had the lowest feed cost (Bangladeshi Taka 136.8 BDT/kg live weight gain), which was increased (147.5 BDT and 153.8 BDT) non-significantly (P > 0.05) with the increasing level of concentrate. The diet consisting of 55% concentrate mixture showed similar results with the diet consisting of 75% concentrate mixture, but was comparatively economic. Therefore, considering the growth performance and cost per kg gain of Brahman crossbred growing calves, it may be concluded that the diet consisting of 55:45 C:R may be used for economic beef production.