PURPOSE: This study aimed to investigate whether genetic variability, assessed through polygenic risk scores (PRSs), predicts blood pressure (BP) changes in individuals with systemic arterial hypertension (SAH), and to explore potential interactions between genetic risk and dietary interventions. METHODS: This study represents a secondary analysis of data from the Brazilian multicentre trial (NUPRESS), which compared a Dietary Approach to Stop Hypertension (DASH) diet (control group) with a multicomponent intervention (intervention group) over 180 days in adults with SAH. Participants underwent anthropometric assessment, cardiovascular risk evaluation, dietary assessment, and genotyping using a genomic microarray. Single nucleotide polymorphisms (SNPs) associated with BP changes were identified and used to construct PRSs. Multiple linear regression models were employed to examine associations between PRSs, dietary interventions, and changes in systolic (ΔSBP) and diastolic BP (ΔDBP). RESULTS: A total of 114 SNPs were associated with ΔSBP and 101 with ΔDBP. The resulting PRSs showed strong correlations with both ΔSBP (r = 0.85; p < 0.0001) and ΔDBP (r = 0.84; p < 0.0001). No significant effect of dietary intervention on BP changes was observed, and no interaction was identified between PRSs and dietary approach for ΔSBP (p = 0.98) or ΔDBP (p = 0.13). CONCLUSION: PRSs derived from BP-associated SNPs were strong predictors of BP changes over six months, independent of dietary intervention. These findings support the potential utility of genetic profiling in predicting individual variability in BP response, although replication in independent cohorts is warranted. Main study trial registration number NCT03793881 on ClinicalTrials.gov.