This study evaluated the efficacy of fenugreek seed extract (FSE) in growing pigs. About 140 growing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 23.70 ± 2.80 kg were used in a 6 wk trial. Treatments were (on as-fed basis) two levels of FSE (FSE0, 0 or FSE0.2, 2 g kg^-1 basal diet), and two levels of energy [low-energy diet (LED); 3160 or high-energy diet (HED); 3260 kcal kg^-1 metabolizable energy (ME)]. Pigs in HED and FSE0.2 diets had higher final BW, average daily gain, and gain:feed ratio (G:F) compared with in LED, and FSE0 diets, respectively (P < 0.05). Pigs fed the FSE0.2 and HED diets had higher energy (E) digestibility than the FSE0 and LED diets, respectively (P < 0.05). Pigs fed the FSE0.2 diet increased serum immunoglobulin G (IgG), and reduced total cholesterol (TC) concentration than the FSE0 diet (P < 0.05). Hydrogen sulfide (H₂S) and ammonia (NH₃) gas emission in FSE0.2 diet were lower than that in FSE0 group (P < 0.05). In conclusion, results indicated that dietary supplementation of FSE improved growth performance, digestibility, serum IgG, reduced serum TC, and noxious gas emission in growing pigs.