Persons with moderate mental retardation were trained to use external memory strategies in order to overcome their working memory limitations. We expected that metacognitive training would allow these individuals to use external memories and that this would be associated with higher recall. It was further hypothesized that the training would be more effective when combined with a short verbalization instruction. Verbalization of one's own thinking and actions should support and reinforce strategic thinking and structure representation. Verbalization should also permit the participants to acquire or access meta-knowledge, one of the basic components postulated for transfer of strategies. Furthermore, performance in analogical tasks should be improved by transferring the use of external memory strategies. The results show that only some of the participants of the experimental group with and without verbalization used the external memory strategy after training. Those who did use the external memory strategy at posttest performed well with regard to recall performance. We concluded that an external memory strategy is required if the task memory load is high and that the memory performance depends on the use of an external memory aid. The problem of transfer to analogical reasoning tasks remained, most likely because how external memories could be used in such tasks was not made explicit, and did the tasks did not allow much use of external memories.