The present study investigated prospective memory in patients with Parkinson's disease (PD) and healthy controls. In addition, the influence of task importance on participants' performance was examined. Experimental settings required participants to focus either on the prospective or the ongoing task. The three main findings are (1) PD patients performed as well on a prospective memory task as healthy controls when the focus was laid on the prospective memory task, (2) their prospective memory performance was impaired when the ongoing activity was stressed, and (3) differences in working memory capacity were related to these differential effects. Results indicate that PD patients can perform event-based prospective memory tasks to a normal degree if the prospective task component is prioritized. Data also suggest that a reduced working memory capacity plays an important role in this process. Findings are discussed in terms of conceptual, methodological, and clinical implications. (JINS, 2007, 13, 888–892.)