BACKGROUND: There is not enough evidence on the combined effects of speed endurance and speed training on sprint performance in youth soccer players. Therefore, the objective of this study was to assess the combined effects of speed endurance and speed training on sprint performance in youth soccer players. METHODS: A total of 18 young male soccer players were randomly allocated to either a conventional training group (CT; N.=9) or a combined training group (TG; N.=9). In both groups, a 90 -min specific soccer program, including speed ladder drills, speed pyramids and football games, were performed 5 x per week over 6 weeks. In the combined training group, an additional training program was completed, consisting of 10 sessions of speed endurance training (15 reps of 6-s all -out running bouts at 100% of maximum running speed followed by 60 s of recovery) and 8 sessions of sprint training performed over the 6 -week period. The participants' 30-m sprint performance was assessed pre and post intervention. RESULTS: A significant change in 30 m sprint time was found within the TG group (mean difference: -0.153 sec, P=0.006) but not in CT (mean difference: -0.0909 sec, P=0.131). CONCLUSIONS: In conclusion, this study demonstrated that speed performance can be enhanced by 6 weeks of speedendurance and speed training in football players. Combined training provides more benefit than performing regular soccer training in youth soccer players.