Recent development of antibiotics-resistance pathogens in poultry which poses threat to human health has necessitated the search for alternative to Antibiotic Growth Promoters (AGPs) to improve gut microflora in poultry diets. One of the alternatives to AGPs is probiotics which are beneficial organisms. Prebiotics, are by-products of digestion of polysaccharides which poultry do not have enzymes to digest are food for probiotics. Advent of enzymes makes this digestion possible. The prebiotic potentials of enzyme supplemented High Fibre Feedstuffs (HFFs) are not known. This study was conducted to assess the prebiotics potential of xylanase enzyme supplemented Palm Kernel Cake (PKC) on broiler chickens (in-vivo). In the absence of xylanase supplementation, there was significant increase in feed intake (P>0.05), significant decrease in weight gain (P<0.05) and significant increase in feed conversion ratio (P>0.05). There were significant interaction between dietary levels of Palm Kernel Cake and enzyme supplementation on Feed Intake, Weight Gain and Feed Conversion Ratio parameters (p<0.05). Enzyme supplementation irrespective of dietary level of PKC caused a reduction in cost of raising 1kg of broiler Chickens. It can be deduced that enzyme supplementation of PKC helped in increasing and improving protein, ether extract and fibre digestibility. The result obtained for the weights of vital organs showed that the birds were in good health conditions. Analysis of gut microflora (Fungi and Bacteria) showed that dietary levels of PKC (10%, 20% or 30% inclusion) with supplementation of enzyme xylanase enhanced the growth of beneficial microbes which resulted in inhibition or elimination of the opportunistic/ pathogenic microbes. The result of the cost benefit analysis also showed that 10% inclusion level of PKC supplemented with xylanase enzyme resulted in reduction of the cost of production with the best improved broiler performance. Use of enzymes is therefore recommended when HFFs are required as prebiotic source in the gut of broilers.