Abstract: The aim of this study was to determine the potential nutritive value of pepper (Capsicum annuum L.) leaves from five pepper species using chemical composition and in vitro gas production technique. Chemical composition including Dry Matter (DM) Crude Protein (CP), Neutral Detergent Fiber (NDF) Acid Detergent Fiber (ADF) and ash were determind. Gas productions were determined at 0, 3, 6, 12, 24, 48, 72 and 96 h incubation times and their kinetics were estimated using the exponential equation Y = A (1 - exp^-ct). The Organic Matter Digestibility (OMD) and Metabolisable Energy (ME) of pepper (Capsicum annuum L.) leaves from five pepper species were estimated. The DM, CP, NDF, ADF contents of leaves from five pepper species ranged from 17.44-19.69, 13.88-18.76, 26.57-32.72 and 15.64-20.98%, respectively. The pepper leaves obtained from Maras species had significantly (p<0.001) higher CP contents than those of Hatay, 46, Balo and Sena species. Although, the NDF content of pepper leaves obtained from Hatay species was significantly (p<0.001) higher than those of Maras, 46, Balo and Sena species the ADF content of pepper leaves obtained from Sena was significantly (p<0.001) higher than those of pepper leaves obtained from Hatay, Maras, 46, Balo and Sena. The gas production rate, potential gas production, ME and OMD of pepper leaves from Sena was significantly (p<0.001) higher than those of pepper leaves from Hatay, Maras, 46 and Balo. The species had a significant effect on the chemical composition in vitro gas production, ME and OMD of pepper leaves obtained after harvest. Despite there are considerable variations in chemical composition of pepper leaves obtained after harvest among pepper species, pepper leaves had high CP and was quite digestible. It appears that pepper leaves obtained after harvest will provide biomass of an acceptable quality for ruminant animals during critical periods when forage shortage occurs.