The primary purpose of any training program is to optimize athlete’s performance during training and competition. To accomplish this goal, coaches and athletes need to design and implement comprehensive training programs which help athletes to have better physiological demands for a specific event. In ball games there are different fitness qualities in which athletes should develop through scientific training. Current handball requires a high level of general and specific fitness. This study was undertaken to find out the effect of small-sided game training on aerobic fitness and repeated sprint ability among project handball players. For this purpose, sixteen male players were selected from woreta city handball project. The selected player’s age was 14.44 ± 0.63 years; height was 143.81 ± 7.65 cm and weight were 39.96 ± 4.96 kg. Based on their pre-test results the samples were divided into 2 groups. The two groups were assigned by lottery system namely Group –A Experimental group and Group B control group and each group consisting of 8 subjects. The experimental group underwent small-sided game Training for a period of 12 weeks and was tested before and after the training. Standardized tests were used to test the selected variables. To see the effect of these training methods and to analyse whether there is a significant different between their pre and post results paired sample t test was employed. In addition to compare difference between the two groups on player’s aerobic fitness and repeated sprint ability, an independent sample t- test with an alpha value of .05 was employed. After twelve weeks of Small-sided game Training the results show that there was a significant difference in all testes. And also, it is noted that results of experimental group in all aerobic fitness tests and RSA (total sprint time & fatigue index) were significantly improved. (i.e., in 2.4 km run test the mean aerobic fitness of Experimental group was 5.58 and 6.75 for Control group, p = 0.014; in 30-meter sprint run test, Total sprint time for Experimental group was 28.52 and 30.91 for Control group, p = .003; Fatigue index for Experimental group was 14.29 and 23.79 for Control group, p = .001). The result from this study confirms that small sided game (4 vs. 4) training method was significantly better training method for improvement of player’s aerobic fitness and repeated sprint ability. Keywords: aerobic fitness, Repeated Sprint Ability and Small-Sided Game Training