O'Connell's relationship with Jeremy Bentham is the subject of frequent comment. However, the nature of this relationship has never been adequately documented, largely because the principal documentary evidence – their correspondence – remains uncollected. As a result, there exists a lacuna in the literature relating to O'Connell's involvement with British radicalism. This essay reconstructs the nature of his political alliance with Bentham from the evidence provided by their correspondence, from 1828 to 1831. It begins with O'Connell's plausible professions of discipleship and their shared optimism about the radical reform agenda, through to Bentham's concerted efforts to bind O'Connell to the British radical movement, and ending in the disillusionment and division that arose from O'Connell's insistence on giving priority to Irish reforms and Bentham's deep suspicion of catholicism. The whole is illustrative of Bentham's efforts in his later years to implement his policies through the agency of presumed ‘disciples’.