The quantity of pentose, hexose and sucrose which are contained in the sap of 16 different plant species of the genus Acer growing in Korea is determined. The results showed that, of these 16 species, Acer mono MAX. contained the largest amount of pentose (20.4%) and that A. mono MAX. var. paxii HONDA contains the next largest(19.7%). Also A. mono MAX. contained the largest amount of hexose (17.4%) and A. mono MAX. var. paxii HONDA contained the next largest(15.1%). The plants which contained the largest amounts of sucrose was A. mono MAX. and A. takesimense $N_{AKAI}$ (1.9%). The plant containing the next largest amount of sucrose was A. tschonoskii MAX. var. rubripes $N_{AKAI}$(1.8%).