Iran is a largest pistachio producer in the world. Typically about 300,000 tonnes were exported to other countries per annum. Total pistachio by-product production in Iran has increased at an average rate of about 400,000 tonnes per year, and is becoming an environmental problem. Pistachio hulls are produced during de-hulling of pistachio nuts soon after harvest. Pistachio hulls contain about 12%crude protein (CP), 5% ether extract, 34% NDF, 21% ADF, 9.20% ash and 8% tannin (DM basis). Using pistachio by-products for ruminant feed could reduce the feed cost, environmental pollution and associated difficulties. This study was conducted to determine whether there is a variation in nutritive value of pistachio by-product during harvesting time.