Living with a chronic condition can challenge a person's identity, yet there is a paucity of research exploring this experience for people with epilepsy and particularly for those diagnosed in adulthood. Consequently, through an interpretative phenomenological approach, the current study aimed to explore what the experience of adult-onset epilepsy meant for a person's identity. Thirty-nine people with adult-onset epilepsy from across the UK took part in up to two semi-structured interviews. A modified form of interpretative phenomenological analysis was conducted and identified three themes: 1) disarming the impact of seizures considered strategies used to control seizure occurrence and regain a sense of control over the body; 2) distinguishing the self from the body highlighted participants' attempts to separate their sense of self from the unpredictability of their bodies; 3) separating epilepsy from themselves demonstrated how participants externalized epilepsy from themselves in order to reject it as part of their identity. The findings highlighted that living with adult-onset epilepsy can challenge a person's sense of self and trust in their body, resulting in the adoption of various strategies to manage the threat to their identity. As such, practitioners must pay attention to the impact that adult-onset epilepsy can have on a person's identity and faith in their body.