The light compensation point was considered as the optimum incident light intensity for storage of green plants under the condition of very low light irradiation (Kozai et al., 1996). However it was obtained from the complicated experiment under various light intensity in previous reports (Fujiwara et al., 1999). A simple theoretical method for estimation of the light compensation point was developed. Namely, the light compensation point lc was derived from the simple equation of φIc＝Rd under the condition of low light irradiation, where φ is the quantum yield; Rd the dark respiration rate. As φ is considered as O.0891 mol CO2 mol quanta－i regardless of species, the light compensation point can be obtained by the equation when the dark respiration rate is determined. The estimated value of the light compensation point was agreed approximately with the experimental value using harvested lettuce independently of the experimental condition. lt is suggested that the developed method may be suitable for the estimation of the light compensation point of other green plant.