Two rare cases of bowler's thumb (traumatic neuropathy of the ulnar digital nerve of the thumb) were treated surgically with encouraging results. These had different types of lesion, involving nodular neuroma and epineural mass, which were distinguished by magnetic resonance imaging. The surgical outcome for active bowlers is unclear and postoperative protection from the repetitive trauma of throwing is important. Possible technical solutions include changing the size and weight of the ball, the spacing between holes, the fitting of thumb to ball, and the slope and size of thumb holes. It is important that both bowlers and clinicians are sufficiently aware of bowler's thumb to allow early diagnosis and treatment of this lesion.