Evidence from multiple large prospective studies suggests that a common polymorphism that encodes an arginine (Arg)–to–tryptophan substitution at position 719 in the KIF6 gene is associated with coronary heart disease (CHD) and reduction in coronary events from statin therapy. Carriers of the 719Arg allele were at greater risk for primary and secondary CHD events, and statin therapy significantly reduced coronary events in 719Arg carriers but not in noncarriers. The number needed to treat to prevent a single CHD event ranged from 10 to 20 for 719Arg carriers, compared to >80 for noncarriers in the Cholesterol and Recurrent Events (CARE) study, the West of Scotland Coronary Prevention Study (WOSCOPS), the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), and the Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis In Myocardial Infarction 22 (PROVE IT–TIMI22) study. In conclusion, assessment of 719Arg carrier status holds promise for stratification of coronary event risk and for selection of optimal therapy in primary and secondary CHD prevention.