Despite the clinical benefit of statin therapy and the numerous strategies used to improve adherence, no strategy has used direct communication of genetic test results to the patient as an adherence and persistence motivator. We investigated in a real-world setting the effect of a process of providing KIF6 test results and risk information directly to 647 tested patients on 6-month statin adherence (proportion of days covered (PDC)) and persistence compared with concurrent non-tested matched controls. Adjusted 6-month statin PDC was significantly greater in tested patients: 0.77 (95% confidence interval (CI) 0.72-0.82) vs controls 0.68 (95% CI 0.63-0.73), P<0.0001. Significantly more tested patients were adherent (PDC⩾0.80) (63.4% (59.6-67.1%) vs 45.0% (41.1-48.8%), P<0.0001) and persisted on therapy (69.1% (65.4-72.5%) vs 53.3% (49.4-57.1%), P<0.0001). Similar results were observed in a secondary comparison with 779 unmatched patients who declined testing. The Additional KIF6 Risk Offers Better Adherence to Statins trial provides the first evidence that pharmacogenetic testing may modify patient adherence.