The Justification for the Use of statins in Primary prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) is a randomized, double-blind, placebo-controlled primary prevention trial of statin therapy among persons with average to low levels of low-density lipoprotein (LDL) cholesterol who are at increased cardiovascular risk due to elevated plasma concentrations of the inflammatory biomarker high-sensitivity C-reactive protein (hs-CRP). A total of 17,802 persons with LDL cholesterol<130 mg/dl (3.36 mmol/L) and hs-CRP>or=2 mg/L were recruited from 26 countries and randomly allocated to 20 mg/day rosuvastatin or placebo. In contrast to previous studies of statin therapy in primary prevention, JUPITER is evaluating a group with modest plasma concentrations of LDL cholesterol (median 108 mg/dl, interquartile range 94 to 119). Further, the trial includes 6,801 women (38.2%) and 5,577 participants with metabolic syndrome (32.1%). Thus, in addition to broadening our understanding of statin therapy and inflammation, the JUPITER trial will provide important and clinically relevant information on primary prevention among patients who do not currently qualify for lipid-lowering therapy. In conclusion, as 20 mg of rosuvastatin can reduce LDL cholesterol by up to 50%, JUPITER will also provide crucial safety data for several thousand patients who should achieve LDL cholesterol levels<50 mg/dl on a long-term basis.