Observational studies suggested that the progression of carotid atherosclerosis and plaques might be an independent risk factor for coronary artery disease (CAD) and stroke, prior researches of different dosage of statins therapy on the progression of carotid atherosclerosis in patients had small sample sizes and different the results. We aimed to evaluate the efficacy and safety of statins therapy on the rate of carotid atherosclerosis progression through randomized controlled trials (RCTs). We searched MEDLINE (1980-September 2003), the Cochrane Controlled Trials Register, EMBASE (1985-September 2003), Science Citation Index and PUBMED (updated through December 2003). Additional articles were obtained from reference lists of relevant reviews and papers in manual searches. Ten studies (eight studies between statins and placebo, two studies between aggressive statins and conventional therapy) were included. Two reviewers extracted abstracts, and appraised the Jadad Score for Grading Quality of Randomized Controlled Trials independently, and discrepancies were resolved by consensus with a third reviewer. We analyzed the 10 trials with 3443 individuals age range from 30 to 70 years old and follow-up for 1-4 years. Eight studies showed that the rates of carotid IMT progression were consistently significantly different between statins and placebo, the Z score for overall effect of IMT was 10.41 (P<0.00001), Total 95%CI of weighted mean difference (WMD) between two groups was -0.02235 [-0.02656, -0.01614] (mm/y), the chi(2)-test for heterogeneity of IMT between eight studies was 685.33 (P<0.00001), two studies between aggressive statins and conventional statins demonstrated that the Z score for overall effect of IMT was 15.85 (P<0.00001), total 95%CI of WMD between two groups was -0.06326 [-0.07108, -0.05544], chi(2)-test for heterogeneity of IMT between two studies was 3.75 (P=0.05). Conventional statins were not significantly different of adverse events and withdrawal than placebo (P>0.05). Our findings suggest that conventional statins therapy are efficient and safe to decrease the rate of carotid atherosclerosis progression in a long-term, and aggressive statins may provide superior efficacy for carotid atherosclerosis regression.