This study was conducted to determine the protein quality of four types of edible mushrooms, Terfezia claveryi, Pleurotus ostreatus, Tricholoma terreum and Agaricus macrosporus that are common in Jordan. Protein efficiency ratio (PER) and net protein utilization methods (NPU) were used. The four mushroom types failed to support growth as reflected by negative values for PER; -1.76 for T. claveryi; -0.23 for P. ostreatus; -0.98 for T. terreum and -0.41 for A. macrosporus. The NPU(op), NPU(st) and NdpE% for T. claveryi were 32.6, 33.9 and 3.89%, respectively. The respective values for P. ostreatus were 38.5, 40.7 and 4.35%; T. terreum 29.1, 29.8 and 3.63%; and A. macrosporus 31.5, 32.9 and 3.91%. The results showed that the four mushrooms were significantly (p < or = 0.05) lower in protein quality compared with casein results (NPU(op), NPU(st) and NDpE% of 78.5, 86.4 and 7.16%, respectively.