Simplified diets aim to maximise the incorporation rate of fodder and/or by-products into animal feed to minimise costs and importation dependency. This study aimed to evaluate the possibility of feeding fattening rabbits with a simplified diet composed of only 2 inexpensive and locally available agro-industrial by-products: brewer's grain and wheat bran. At weaning (35 d of age), 68 rabbits were divided into 2 groups (mean body weight: 833 +/- 126 g) and housed in individual cages until slaughter (77 d). Rabbits were fed ad libitum either a commercial pelleted feed (control: BO group), or a simplified pelleted experimental diet (SF group) containing 72% wheat bran and 27% brewer's grain. The feed conversion ratio was similar in the 2 groups (3.55 on av). The daily weight gain and daily feed intake were 12% higher (P<0.001) in the BO group than in the SF group (35.2 vs. 31.2 g and 128.3 vs. 113 g/d). The cold carcass yield (+4 percentage points) and carcass weight (+9%) were higher (P<0.001) in BO than in SF group. The carcass was less fatty in SF than in BO group (perirenal fat: -23%, inguinal fat: -41% and scapular fat: -14%). The economic efficiency was 40% better when rabbits were fed SF diet (+0.37 sic/kg of meat) in current local market conditions.