Prospective memory (PM), remembering to perform an action in the future, is an important ability in everyday life. It involves a prospective component, remembering that you have to do something, and a retrospective component, remembering what action to perform and when to perform it. Researchers have pointed to a role of cognitive factors, such as individual differences in working memory (WM), in determining PM performance. Previous studies have found a positive relationship between WM span and PM (e.g., R.E. Smith, Persyn, & Butler, 2011). The goal of the present study is to apply a hierarchical modeling approach to investigate how WM is related to the prospective and retrospective components of PM.