The "athlete anterior repolarisation pattern", characterised by J-point elevation with ascending convex ST-segments and anterior T-wave inversion (ATWI) confined to leads V1-V4, has been considered a normal finding in athletes of Black ethnicity (African-Caribbean descent). This repolarisation pattern was considered to potentially represent an underlying cardiomyopathy in non-Black athletes although recent studies have challenged this. We assessed the prevalence and significance of ATWI among professional Black and non-Black football players in the UK. Athletes underwent pre-participation screening (2017-2024), including a health questionnaire, a 12-lead ECG and an echocardiogram. ATWI was defined as TWI confined to leads V1 to V3 or V4. Ethnicity was categorised as Black or non-Black. 10 955 athletes were studied, comprising 9009 (82.2%) males and 1946 (17.8%) females. 2372 (21.7%) athletes were of Black ethnicity and 8583 (78.3%) were non-Black. Black athletes were marginally younger (18.3±3.8 vs 19.2±4.7 years; p