Class of 2015 Abstract / Objectives: To establish the impact pharmacists can have on adult immunization rates by having pharmacists available to provide, administer, and advocate for immunizations. Methods: The following databases were searched from inception to November 2014: NLM PubMed; Ovid/MEDLINE; and Google Scholar. Inclusion criteria were comparative studies reporting pharmacist intervention and their impact on immunization rates. Of 38 publications originally identified, 15 met inclusion criteria. Variables examined included study characteristics, pharmacist intervention, and immunization rates. Results: Of the 15 studies we identified, only ten studies could be analyzed in the meta-analysis. All studies showed increases in immunization rates with pharmacist involvement, but there was high variance. Pharmacist interventions at hospital sites had the greatest benefit for increasing immunization rates (average odds ratio [OR], 10.64, confidence interval [CI] 95%, 5.25-21.49). Pharmacist intervention at one or two community sites had the second highest impact (OR, 2.81; CI 95%, 2.31-3.41). Studies covering multiple sites (more than two) showed the lowest increase in immunization rates (OR 2.26; CI 95%, 1.81-2.81). Conclusions: Pharmacist’s involvement in advocating and administering immunizations directly increases immunization rates in some patient populations. The greatest increases in immunization rates can be seen when pharmacists advocate for immunizations in the hospital setting.