This study explored problems older adults experience when using a mnemonic technique known as the method of loci. Older subjects received six hours of imagery, judgment, and relaxation pretraining followed by mnemonic training for either four or six hours (Regular or Extended training, respectively). At the end of training, subjects were given a list of the constituent steps of the method of loci and asked to indicate which, if any, were problematic. The factor structure of the relations among the problems varied according to the length of the training subjects received. Specifically, the factor structure of the difficulties reported by the Regular training group reflected problems with using the steps involved in the application of the method of loci, whereas for the Extended training group the factor structure reflected problems with abilities called upon in using the technique. Thus, even with Extended training, subjects may need additional pretraining to develop specific abilities necessary for the successful application of the mnemonic.