OBJECTIVES:  Approximately 70,000 refugees are resettled to the US each year, and it is important that refugees receive immunizations to prevent communicable disease. The measles, mumps, rubella (MMR) vaccination is a two-part vaccination that protects against three diseases. This study sought to identify factors associated with MMR vaccination series completion in a refugee population resettled in the US. METHODS:  We analyzed data from the Jefferson Longitudinal Refugee Health Registry, which contains clinical, demographic, and immunization data. The study population included refugees resettled to the US who received an initial domestic medical examination and follow-up care from a primary care clinic in Philadelphia from 2008-2014. Those not eligible for MMR vaccination per Advisory Committee on Immunization Practices guidelines were excluded. Prevalence of MMR completion was computed. Binomial logistic regressions were used to estimate the association of clinical and demographic factors with MMR series completion. RESULTS:  Of the 1,150 refugees included in the study, 69% were 18-45 years old and 11% were under the age of 18. Forty-six percent of refugees had documentation of MMR vaccination series completion. Age group was significantly associated with MMR completion. Patients 4-11 years old were most likely to complete the series (OR 136, 95%CI:45-419) compared to 65+ year-old patients. Country of origin was associated with increased MMR completion for patients from Myanmar who transited through Thailand (OR 4.7, 95%CI:2.7-8.4), Myanmar who transited through Malaysia (OR 2.9, 95%CI:1.8-4.7), Bhutan/Nepal (OR 5.5, 95%CI:3.6-8.2), and Eritrea/Ethiopia (OR 2.2, 95%CI:1.2-3.8) compared to Iraqi patients. Hypertension and diabetes diagnoses were not found to be significantly associated with MMR series completion. CONCLUSIONS:  Age and country of origin were significantly associated with MMR completion. These findings can be used to identify quality improvement projects to ensure vaccination completion within a recently resettled refugee population.