The aim of this study was to analyse the effect of different small-sided and conditioning games with different tactical contents on heart rate responses, technical performance and collective organization of youth basketball players from different sports levels. Twenty male basketball players from U14 (13.7 ± 0.8 years old; 4.2 ± 1.4 years of practice) and U16 (15.3 ± 1.1 years old; 6.4 ± 2.1 years of practice) participated in this research study. The two-way MANOVA revealed that the sports level (p = 0.009; = 0.151), format (p = 0.001; = 0.246) and task condition (p = 0.023; = 0.104; small effect size) had significant main effects on heart rate responses. It was also found that the format (p = 0.001; = 0.182) had significant main effects on the technical performance. Smaller format significantly increased the heart rate, volume of play, efficiency index and collective density during attacking plays. The SSCG with attacking content statistically increased the heart rate, efficiency index and performance score. Therefore, this study revealed that different SSCGs with tactical content influence the physiological responses of youth players.