A feeding trial was conducted to investigate the effect of palm kernel cake fermented (FPKC) by Paenibacillus polymyxa ATCC 842 on nutrient digestibility, villi height, and gut microflora. A total of 245 one-day-old broiler chicks (Cobb500) were purchased from a local hatchery and raised in an open house system in the research unit at Universiti Putra Malaysia. The chicks were individually wing-banded, weighed and randomly distributed into seven groups with five replicates (pens) and seven birds per pen. The birds were fed diets containing 0, 5, 10 and 15% palm kernel cake (PKC) and 5, 10, 15% FPKC. All the birds were fed ad libitum during the feeding trial, which lasted 42 days. One bird and two birds per replicate in each dietary treatment were randomly selected at 3 and 6 weeks, respectively. Ileal digesta and small intestinal tissues were collected. The findings showed that feeding of 10% or 15% PKC led to a significant decrease (P<0.05) in nutrient digestibility compared with the control group, whereas feeding of 10% or 15% FPKC led to a significant improvement (P<0.05) in nutrient digestibility (except in nitrogen free extract at 3 weeks of age) compared with those groups of birds fed with PKC. No significant differences (P>0.05) were observed between the dietary treatments in terms of intestinal morphology. However, gut microflora were improved (P<0.05) in a group of birds fed with 15% FPKC compared to the other dietary treatments. In conclusion, the current experiment showed that FPKC by P. polymyxa ATCC 842 could be fed to broiler chickens up to 15% in their rations without any adverse effect on nutrient digestibility.