This study was conducted to investigate the proximate composition, free sugars, amino acids, and minerals in five Lentinula edodes cultivars collected in Korea. No significant differences in the content of crude fat and crude fiber were found between the samples; however, there was significant variation in the contents of nitrogen free extract, ash, and crude protein. Three kinds of free sugars (fucose, arabinose, and glucose) were identified by HPLC, with the glucose content ranging from 5.94% to 12.08%. Sixteen kinds of free amino acids were identified: the highest content of amino acids was found in ‘Sanlim5ho’ (13,768.33 mg%), while the highest content of free amino acids was found in ‘Sanlim4ho’ (6,790.57 mg%). The minerals detected in the L. edodes cultivars were potassium, calcium, magnesium, and sodium, the contents of which ranged from 567.16–2,356.09 mg%, 3.85–7.42 mg%, 9.79–20.88 mg%, and 19.60–22.62 mg%, respectively.