The purpose of this study was to examine how to understand the task request on a problem solving situation in mentally retarded children (MA-7:5, 11:9). The cognition of task request was investigated through two aspects of directed and undirected task requests. To clear their cognition for each task request, insufficient instructions were given to children in problem solving situation. Retarded children at MAs of 7 years did not correspond to the latent task request but did to the manifest one; however, those of 11 years corresponded not only to the manifest task request but also to the latent one. Given more instructions in order to make the latent task request explicit, most of the retarded children with MA-7:5 changed in their performance.