The aim of this investigation was to determine the effects of inspiratory muscle training(IMT) on maximal aerobic exercise performance in amateur soccer players. 14 male soccer players were randomly assigned to Inspiratory muscle training group(IMTG, n=7) or Control group(CG, n=7). Both group performed incremental treadmill test using Bruce protocol to examine maximal aerobic exercise performance before and following 8 weeks of intervention. IMTG were given inspiratory pressure threshold device(POWERbreathe) for IMT. All subjects also completed the winter training programme during the 8 weeks intervention. After intervention, there was significant change in VO2/kg between groups(p=0.006). IMTG showed significant changes in VO2/kg(22.15%, p=0.046), METS(21.53%, p=0.048), VT(22.36%, p=0.035) in measured AT values. There was significant change in treadmill exercise time between groups(p=0.001) and IMTG had significant change in treadmill exercise time(19.26%, p=0.001) after 8 weeks intervention. These results support evidence that inspiratory muscle training(IMT) has beneficial effects on VO2/kg, METS, VT and treadmill exercise time and might be a factor that improve soccer players` exercise performance.