Evapotranspiration from a sugar cane field was observed during the summer season in the Miyako Islands. Interpolation was also conducted for the data deficit period by using the bulk transfer coefficient and evapotranspiration efficiency, which were represented as a function of solar radiation and soil water content. Evapotranspiration was 6.4 mm day^-1 in late June, and decreased gradually. It was under 3.5 mm day^-1 (100 W m^-2) at the end of October.