The process leading to coronary atherosclerosis is initiated in childhood (Mc Gill et al. 2000) and so reducing postprandial triacylglycerol (TAG) concentrations, even in young people, could potentially slow atherogenic progression. This study sought to investigate if continuous exercise and intermittent games activity would reduce postprandial TAG concentrations in adolescent boys. Nineteen participants took part in this study and were randomly assigned to either a continuous exercise group (n = 10, age 15.3 ± 0.1 years, height 177.1 ± 1.7 cm, body mass 63.4 ± 1.1 kg and pubic hair maturity 4 ± 1; mean ± S.E.M.) or an intermittent games activity group (n = 9, age 15.4 ± 0.1 years, height 177.5 ± 1.2 cm, body mass 59.8 ± 1.0 kg and pubic hair maturity 4 ± 1; mean ± S.E.M.) and underwent two 2-day trials. Trials were performed a minimum of 7 days apart in a randomised, counterbalanced order consisting of a rest and exercise trial. Participants were asked to control their physical activity levels and diet before each trial. The study had ethical approval and prior to testing, written informed consent was obtained from parents/guardians. Maturity was self-assessed (Tanner, 1962). In the rest trial participants took no exercise on day 1. On day 1 of the exercise trials participants completed four blocks (approximately 15 min per block) of uphill treadmill walking (continuous group) or intermittent games activity (intermittent games group). On day 2, participants came to the laboratory after an overnight fast and finger prick blood samples were obtained in the fasted state. Participants then ingested a test meal (1.25 g fat, 1.07 g carbohydrate, 0.20 g protein, and 67 kJkg^-1 body mass). Further finger prick samples were collected at 30 and 45 min and 1, 3, 4 and 6 h. Plasma samples were analysed for TAG. Data were assessed using Student’s t test for correlated means. Triacylglycerol data were logarithmically transformed prior to statistical analysis to achieve normality. Statistical significance was accepted at the 5% level. The total area under the TAG versus time curve was lower in the exercise compared with the rest trials in both groups (continuous exercise group: 7.26 ± 0.82 versus 8.39 ± 0.75 mmol l^-1 (6 h)^-1, exercise versus rest, respectively, reduced by 14%, P = 0.050; intermittent games activity group: 6.92 ± 0.79 versus 9.38 ± 1.25 mmol l^-1 (6 h)^-1, exercise versus rest, respectively, reduced by 26%, P = 0.002, no difference when groups compared). Both continuous exercise and intermittent games type activity reduce postprandial TAG concentrations in adolescent boys.