Washington State has some of the highest percentages of school immunization exemptions in the country. We compared school immunization records in a rural school district in Pierce County, Washington, to immunization records in the state immunization information system (IIS) and parent-held records. Correcting school immunization records resulted in an increase in the number of students classified as fully immunized from 1,189 to 1,564 (p less than 0.0001). We conducted school-based immunization clinics that increased the number of fully immunized students to 1,624 (p = 0.013). Immunized students with certificates of exemption on file suggest exemptions of convenience. Strategies to improve school immunization services include assigning IIS access to school administrative staff and educating school staff and parents on the importance of immunization. (Contains 1 table.)