The present study was investigated the effects of dietary Achyranthes japonica extract ( AJE) supplementation on the growth performance, total tract digestibility, cecal microflora, excreta noxious gas emission, breast meat quality, and organ weight in broiler chickens. In total, 640 Ross × Ross male broiler chickens (1-day-old) were randomly distributed into 4 dietary treatments with 10 replicate cages (16 birds/replicate) per treatment group for 5 wk. The dietary treatments included a control basal diet without AJE, and diets with 0.025, 0.05, or 0.1% AJE. Body weight gain, feed intake, and feed conversion improved linearly with the supplementation of AJE over the experimental period (days 1 to 35) ( P < 0.05). Dietary AJE supplementation caused a significant increase in the apparent total tract digestibility of dry matter and nitrogen (linear, P < 0.05). The cecal Lactobacillus, E. coli, and Salmonella counts were linearly affected with increasing dietary AJE supplementation ( P < 0.05). With increasing levels of AJE, excreta ammonia gas concentration showed a linear decrease ( P < 0.05). The breast muscle weight linearly increased, along with a decrease in the abdominal fat weight, in treatment groups fed with AJE ( P < 0.05). These results indicate that dietary addition with increasing AJE linearly improved growth performance, total tract digestibility, cecal microflora, excreta ammonia gas emission, and abdominal fat weight in broiler chickens.