There is limited evidence on association between adherence to the Dietary Approaches to Stop Hypertension (DASH diet) and a lower blood pressure (BP) in children. In a population-based cohort study, among 1068 Dutch children aged 5 to 7, we evaluated the association between a DASH-type diet, 29 known genetic variants incorporated in a genetic risk score, and their interaction on BP. We calculated DASH score based on the food intake data measured through a validated 71-item food frequency questionnaire. In our sample, DASH score ranged from 9 (low adherence to the DASH diet) to 33 (median=21), and genetic score ranged from 18 (low genetic risk on high BP) to 41 (median=29). After adjustment for covariates, each 10 unit increase in DASH score was associated with a lower systolic BP of 0.7 mm Hg ( P =0.033). DASH score was negatively associated with hypertension (odds ratio=0.96 [0.92–0.99], P =0.044). Similarly, each SD increment in genetic score was associated with 0.5 mm Hg higher diastolic BP ( P =0.002). We found a positive interaction between low DASH score and high genetic score on diastolic BP adjusted for BP risk factors (β=1.52, P _interaction =0.019 in additive scale and β=0.03, P _interaction =0.021 in multiplicative scale). Our findings show that adherence to the DASH-type diet, as well as a low (adult-derived) genetic risk profile for BP, is associated with lower BP in children and that the genetic basis of BP phenotypes at least partly overlaps between adults and children. In addition, we found evidence of a gene-diet interaction on BP in children.