Abstract. This paper is concerned with arti cial evolution of neurocontrollers with adaptive synapses for autonomous mobile robots. The method consists of encoding on the genotype a set of local modi cation rules that synapses obey while the robot freely moves in the environment 2]. The synaptic weights are not encoded on the genotype. In the experiments presented here, a \behavior-based tness" function gives reproductive advantage to robots that can solve a sequential task. The results show that evolutionary adaptive controllers solve the task much faster and better than evolutionary standard (non-adaptive) controllers, that the method scales up well to large architectures whereas standard controllers do not, and that evolved adaptive controllers are not trivial and cannot be reduced to a xed-weight network. 1 Evolution and Learning Arti cial evolution of adaptive individuals can providecomputational advantages and richer adaptive dynamics 1] with respect to evolution of individu...