The aim of this study was to analyse the role of a relative age effect (RAE) and to investigate the influence of biological maturity status on the RAE at the 7^th International Children`s Winter Games. The birth dates of all 572 participants (365 males, 207 females) were analysed, and the biological maturity status of 384 athletes (243 males, 141 females) was assessed by the age at peak height velocity (APHV) method. A RAE was present in the total sample (χ² = 67.81; p < 0.001), and among both male (χ² = 49.02; p < 0.001) and female athletes (χ² = 37.00; p < 0.001) as well as for strength- (χ² = 56.46; p < 0.001), endurance- (χ² = 20.48; p = 0.039) and technique-related types of sports (χ² = 20.48; p = 0.041). No significant differences in biological maturity status were present between the male athletes of single relative age quarters. Among the female athletes a significant difference was present (F = 5.94, p < 0.001); relatively younger female athletes had significantly lower values in the APHV, which indicated that they were maturing earlier. However, when dividing the athletes into normal, early and late maturing athletes, it could be seen that among the relatively younger athletes, hardly any late maturing athletes were present. These findings revealed that relatively younger athletes seemed to only have a chance for selection if they were early maturing, whereas relatively older athletes had an increased likelihood for selection independent of their biological maturity status. In the future, the relative age and the biological maturity status should be considered in the talent development system for various types of winter sport, to contribute to more fairness and to not discriminate against relatively younger and less mature athletes.

• The relative age strongly influenced the participation rate at the 7^th ICG in 2016.

• A highly significant RAE was present among male and female participants and among athletes of all three groups of sport disciplines: strength-, endurance- and technique-related types of sport.

• A significant influence of the biological maturity status on the selection was present among female participants – relatively younger female athletes were more mature than relatively older athletes.

• Relatively younger male and female athletes seem to only have a chance for selection for the Games if they are early maturing, whereas relatively older athletes have an increased likelihood for selection independent of their biological maturity status.

• In the future, the biological maturity status and the relative age should be considered in the talent development system for various types of winter sport, to contribute to more fairness and to not discriminate against relatively younger and less mature athletes.