The purpose of this study was to investigate the effect of six weeks concurrent and circuittraining on aerobic power in adolescent male soccer players. Twenty-four soccer players (meanage 13.85±0.52 years and mean weight 51.96±8.22 kg) were randomly assigned to two traininggroups: 1-Concurrent training (n=12) group performed two training programs: resistancetraining that involved 3sets exercises in the first four weeks and 2sets exercises in the last twoweeks (%65 to %75 one RM;8 rep) and endurance training that included 3 repetitions run in thefirst four weeks and 2 repetitions run in the last two weeks(10 min ;%65 to %75 maximalHR).They performed training programs with an interrupt between two session; and in the lasttwo weeks they did the both training in one session.2- Circuit training group (n=12) carried outthe training in ten stations exercises(%70 to%80 maximal HR).All the subjects were evaluatedbefore and after the training period using 1 mile test(aerobic power). For analyzing the data weused t-test dependent samples. Result of this study showed that aerobic power of the playerswithin both groups after six weeks had significant increase... Therefore; it is expected that theboth circuit and concurrent training have great influence on aerobic power of adolescent malesoccer players.