The association between statins and diabetes mellitus (DM) remains controversial. The Kaiser Permanente CHAMP Study identified adults without DM who had cardiovascular (CV) risk factors and no previous lipid lowering therapy (LLT) between 2008 and 2010. The CV risk factors included known atherosclerotic CV disease (ASCVD), elevated low-density lipoprotein cholesterol ≥190 mg/dl, or a low-density lipoprotein cholesterol between 70 and 189 mg/dl and an estimated 10-year ASCVD risk ≥7.5%. Incident DM was defined as ≥2 abnormal tests (i.e., A1C ≥6.5% or a fasting blood glucose ≥126 mg/dl) or ≥1 abnormal test result plus a new diagnostic code or medication for DM. Among 213,289 eligible adults, 28,149 patients initiating statins were carefully matched to an equal number of patients who remained off LLT during follow-up. Compared with matched patients not receiving statins, those initiating statin therapy had the same mean age (67.9 ± 9.4 years) and gender (42.8% women). The crude rate (per 100 person-years) of incident DM was low (0.55, 95% confidence interval [CI] 0.52 to 0.59) but was marginally higher in patients who were treated with a statin (0.69, 95% CI 0.64 to 0.74) versus no LLT (0.42, 95% CI 0.38 to 0.46). After additional adjustment, statin therapy was associated with a modestly increased risk of incident DM (adjusted hazard ratio 1.17, 95% CI 1.02 to 1.34). In conclusion, in adults without DM at increased ASCVD risk, initiation of statin therapy was independently associated with a modestly higher risk of incident DM.