The importance of poultry industry in Pakistan is not only because it provides animal proteins to rapidly growing human population but also it has momentous share in the economy of the country. The total poultry population in Pakistan is 663 million with 542.74 million broilers. This sector produces 767 (000 tones) meat annually that is 24.8% of total meat production in the country. Profitable poultry production is possible if balanced and cost effective diets are formulated. Poultry production is handicapped because of high feed cost as it accounts up to 70% of total cost of production. The high price and limited quantities of conventional protein feed ingredients always provoke avian nutritionists to explore the nutritional potential of un-traditional protein sources in terms of their biological evaluation. Usage of non-conventional ingredients plays their part to bridge the nutrient gap and make feed formulation more versatile. Corn steep liquor (CSL) is one of such untraditional by-products of corn wet-milling industry that can be used as feed ingredient in poultry diet. High protein content of CSL makes it an excellent protein source to be used in poultry diet.