Multitasking refers to the performance of several tasks in a limited time frame, such an ability is essential for everyday life. It has been proposed that there is an age-related difference in multitasking, with a decline with age. However studies investigating such differences have produced mixed results. The current cognitive model of multitasking by Burgess and colleagues (2000) proposes that it is underpinned by three cognitive constructs: retrospective memory, prospective memory and planning. This study aims to investigate whether age-related differences in multitasking exist by comparing healthy young adults (M=23.40, SD=3.86) to healthy older adults (M=69.00, SD=5.99). The cognitive processes that may underpin multitasking in young and older adults are investigated. The cognitive processes examined are those proposed by Burgess and others (2000) and EFs hypothesised by us to be related to multitasking – initiation, switching and time estimation. Age-related differences were found in our measure of multitasking, with young adults performing significantly better than older adults. Correlational analysis found the young’s multitasking ability to be related to retrospective memory, prospective memory and initiation, suggesting these cognitive processes underpin their multitasking. The older adults multitasking ability was found to be related to retrospective memory and prospective memory, suggesting these cognitive processes underpin their multitasking. It was discovered that retrospective memory predicted a significant proportion of the variance in multitasking ability for young adults. This finding was not replicated in older adults. Therefore while retrospective memory underpinned both young and older adult’s ability to multitask, it was not predictive of the older adult’s ability, only the young adults. This suggests that the old and young adults differ in the cognitive processes that predict their ability to multitask. How these findings relate to previous literature is addressed in the discussion. Strengths, limitations and implications of this study are outlined and possible future studies discussed.