This study aimed to explore the effect of recorded verbal prompts on helping an adult with severe mental retardation to take bath independently. A single-subject experiment with「A-B-A-C-A-C」design was adopted. The experiment consisted three phases-baseline phase (A), intervention phase (B): verbal prompt, and intervention phase (C): tape-recorded verbal prompt. A female with severe mental retardation participated in the experiment. It took over seven months to finishing the intervention. The results of the experiment indicated that verbal prompts, whether human verbal prompt or recorded prompt, could help the client to take bath more independently. The families of the client also regarded recorded verbal prompt was a feasible solution. Based on the result, there were some suggestions for the further research.