A systematic review of the literatures was conducted to evaluate the effect of clinical practice guideline. The 77 studies were identified from a computerized search of published research on MEDLINE, Science-Direct and Blackwell synergy from January, 1997 to October, 2007. The main search terms were "clinical practice guideline" and "effectiveness", "clinical practice guideline" and "impact", "clinical practice guideline" and "evaluation". These studies were assessed the Quality twice by one Qualified expert and converted into weighted scale. The 63 studies were eligible inclusion criteria and subdivided into type of effect. Final indicator using for policy effect of clinical practice guidelines were classified as 4 categories; "improvement of outcomes" in 81 studies, "betterment in practice patterns" in 68 studies, "rationalization in resource utilization" in 84 studies and "cost containment" in 31 studies. The vote-counting method, one of meta-analysis method, was applied to summarized the effect of clinical practice guidelines and test statistically. From results of meta analysis, all indices were statistically significant. In conclusion, this meta-analysis showed that introduction of clinical practice guidelines were resulted positive outcomes in health policy.