Autobiographical memory is severely impaired in Alzheimer's disease (AD). However, previous research has focused primarily on voluntary memories-that is, memories retrieved deliberately following a request. Here we investigated the extent to which people with AD experience involuntary (spontaneous) autobiographical memories (IAMs), using a novel method to simulate involuntary retrieval in naturalistic settings. Twenty-one AD patients and 22 healthy controls viewed nostalgia films designed to elicit IAMs under two conditions: with or without prior reminiscence. AD patients expressed more IAMs and emotional reactions overall and showed higher physiological reactivity in response to the films than controls. Both groups verbalized more IAMs after having engaged in reminiscence prior to watching the film. The results provide novel evidence that AD patients frequently engage in involuntary remembering when viewing media content dated to their youth, suggesting that involuntary retrieval may act as an alternative route for accessing the personal past in AD.