Chemobrain is one of the most commonly reported side-effects of cancer treatment. However, there is limited research into its psychosocial concomitants. This study aimed to explore the long-term lived experience of chemobrain. Interpretative phenomenological analysis allowed an in-depth investigation of 12 breast cancer survivors suffering from perceived cognitive deficits at least 1-year post-treatment. Themes were organised around the illness representations framework. Commonly reported cognitive deficits related to memory, language and processing speed, which affected participants’ sense of identity and their interactions with others. Individual experiences were mediated by health beliefs regarding controllability, validation and impairment trajectory.