We examined effects of a 3-month football training programme in overweight children using comprehensive echocardiography and peripheral arterial tonometry. Twenty preadolescent overweight children (17 boys, 3 girls aged 8-12 yrs; body mass index [BMI] ≥ 85(th) percentile) participated in a structured 3-month football training programme, consisting of 4 weekly 60-90 min sessions with mean heart rate (HR) > 80% of HRmax (football group, FG). A parallel control group (CG) included 11 children (7 boys, 4 girls) of equivalent age from an obesity clinic. After 3 months, systolic blood pressure was unchanged in FG, but had increased in CG (112 [s 6] vs. 122  mmHg, P = 0.02). FG demonstrated increased left ventricular (LV) posterior wall diameter (0.60 [0.07] vs. 0.68 [0.10] cm, P < 0.001) and an improved right ventricular systolic function determined by tricuspid annular plane systolic excursion (TAPSE, 2.01 [0.29] vs. 2.27 [0.28] cm, P = 0.003). Measures of LV systolic function showed only discrete alterations and two-dimensional (2D) global strain was not changed. After 3 months, global isovolumetric relaxation time (IVRTglobal) had increased in FG (64.0 [7.5] vs. 73.9 [9.4] ms, P < 0.001) while other examined LV diastolic function variables were not altered. No echocardiographic changes were observed in CG. Between-group differences in pre-post delta values were observed for systolic blood pressure, TAPSE, and IVRTglobal (P = 0.02-0.03). We conclude that short-term football training may have positive structural and functional effects on the cardiovascular system in overweight preadolescent children.