Background and Study Aim Material and Methods Results Conclusions Small-sided games (SSG) are frequently used by coaches due to the effect of soccer players in improving their technical, tactical, and physical characteristics in training. When we try to improve of our players talent, we must know what kind of changes happen in blood samples. For this reason, we aimed to determine of cytokine responses to SSG in young soccer players. Fourteen active male soccer players (14.5± 0.6 years) in the Under-14 and Under-15 teams voluntarily participated in the study. Soccer players are divided into 2 groups as 3x3 and 4x4 groups. 3x3 group players played 2x6x1 minutes small-sided games in 25x20 m area and 3x6x2 minutes small-sided games in 30x25 m area for 4x4 group players. Blood samples were collected at baseline pre-training and at immediately after the exercise post-training to measure interleukin 6 (IL-6), tumor necrosis factor (Tnf-α), and lactate (La) parameters. And also, heart rate (HR) and rating of perceived exertion (RPE) determined both pre-training and post-training. In the study, post training levels of La, IL-6, Tnf-α, HR, and RPE both in 3x3 group and in 4x4 group were found to be significantly higher than pre-training (p<0.05). When the post training parameters of both groups were examined, only the Tnf-α level increased significantly in the 4x4 group (p<0.05), while no difference was found in the other parameters (p>0.05). Small sided games which are acutely applied in young soccer players, both 3x3 group and 4x4 group is are similar. However, with a more players can increase tnf-α released and this can effect performance as negatively in young soccer players.