The purpose of this study was to analyse the relative age effect (RAE) in all age categories in the development programme of a professional football club and to identify whether playing time and the chances of debut in the first team are influenced by the RAE. We examined the birth-date distributions of 334 elite football players from Real Club Deportivo de la Coru\u00f1a: 195 young soccer players (DTG) divided into 11 age groups (U-9 to U-23), 110 professional players (FTG), and 29 players who debuted in competitive matches with the club\u2019s first team from the youth development programme (EG). Playing time was calculated by adding up all the minutes played by a player in official competition during a season. The Chi-square test results show that the RAE exists in the 3 groups and in all the 11 age groups of the DTG players. The RAE was significantly lower in the FTG compared to the DTG and EG groups (Mann-Whitney U test, p\u2009<\/em><\u20090.05). There were no differences in playing minutes between players born in the first half of the year or in the second half of the year. These findings suggest that the RAE in elite clubs originates fundamentally in the talent selection process in all categories, but mainly in the youngest ones, and is maintained in all the lower categories, influencing the chances of making a first-team debut.<\/p>\n\n