Traditional doenjang with Lentinus edodes added at a concentration of 0, 3, 5 and 10% (w/w) was prepared and its physicochemical characteristics were analyzed during fermentation for 6 months. The moisture content, salt level and pH for doenjang were decreased with increasing addition of Lentinus edodes powder, but crude protein content was increased. Among the free sugars, glucose, galactose, arabinose, sucrose and maltose were identified and quantified, with the first two being the major free sugar. Minerals were detected in the order of Na> K> P> Ca> Mg> Fe while the content of Cu, Mn and Zn exhibited little change. The contents of each amino acid of traditional doenjang with added Lentinus edodes, glutamic, leucine and aspartic acids, had a much higher level. In fatty acid compositions, palmitic, stearic, oleic and linoleic acids were analyzed, with oleic acid being the most abundant fatty acid at $56.4{pm}0.8sim57.5{pm}0.5%$ in all the tested samples. GMP and IMP contents of nucleotides and their related compounds were extremely high. It was thought that these substances contributed to the sweet taste of traditional doenjang with added Lentinus edodes. These results showed the applicability and high quality of traditional doenjang with added Lentinus edodes.