Wave overtopping discharge of gently sloping revetment was evaluated in comparison with vertical-type seawall based on the experimental results given by Tamada et al. There are many cases that the gently sloping revetment is built in front of the existing seawall, because of the limitation of coastal land in Japan. However, this causes increase in wave overtopping over the revetment. This kind of application of gently sloping revetment must be avoided.