The attractiveness of synthetic sex pheromones of the rice leaf bug, Trigonotylus caelestialium (Kirkaldy), was evaluated in the field. The rubber septum was soaked in synthetic sex pheromone, mixture of n-hexyl n-hexanoate, (E)-2-hexenyl n-hexanoate, n-octyl n-butyrate in ratios of 100 : 40 : 3. The rubber septum was used as a lure and was hung on a water pan trap about 10 cm above the water surface. The attractiveness of the synthetic pheromone at 0.001 mg and 0.01 mg per rubber septum to males was equal to that of 10 virgin females. The rubber septum impregnated with 0.01 mg synthetic pheromone remained attractive to males for one month.