The day-out task (DOT), a naturalistic task that requires multitasking in a real-world setting, was used to examine everyday functioning in individuals with mild cognitive impairment (MCI). Thirty-eight participants with MCI and 38 cognitively healthy older adult controls prioritized, organized, initiated, and completed a number of subtasks in a campus apartment to prepare for a day out (eg, determine and gather change for bus, bring a magazine). Participants also completed tests assessing cognitive constructs important in multitasking (ie, retrospective memory, prospective memory, planning). As compared with controls, the MCI group required more time to complete the DOT and demonstrated poorer task accuracy, performing more subtasks incompletely and inaccurately. Despite poorer DOT task accuracy, the MCI and control groups approached completion of the DOT in a similar manner. For the MCI group, retrospective memory was a unique predictor of the number of subtasks left incomplete and inaccurate, while prospective memory was a unique predictor of DOT sequencing. The DOT measures, but not the cognitive tests, were predictive of knowledgeable informant report of everyday functioning. These findings suggest that difficulty remembering and keeping track of multiple goals and subgoals may contribute to the poorer performance of individuals with MCI in complex everyday situations.(PsycInfo Database Record (c) 2020 APA, all rights reserved)