We examine consumers' forgetting to buy items they intended to buy. We show that the propensity to forget depends on the types of items consumers intend to purchase and the way consumers shop. Consumers may shop using a memory-based search by recalling their planned purchases from memory and directly searching for the products. For example, consumers may use the search function at an online store. Alternatively, consumers may use a stimulus-based search by systematically moving through a store, visually scanning the inventory and selecting the required items as they are encountered. Using an online shopping paradigm, we show that consumers are more likely to forget the items they infrequently buy when using the memory-based search, but not when using the stimulus-based search. In fact, when using the stimulus-based search, consumers are sometimes even better able to remember the items they infrequently (vs. frequently) buy. Moreover, consumers fail to take these factors into account when predicting their memory. As a result, they do not take appropriate actions to prevent forgetting (e.g., using a shopping list).