This study explores the impact of the arrival of Syrian refugees in Turkey on access to health-care resources and subsequent changes in infectious disease rates among native children. Employing a distance-based instrument, it finds that native children living in regions that received large inflows of Syrian refugees experienced an increase in their risk of catching an infectious disease compared to children in less affected regions. In contrast, there is no evidence of significant changes in the incidences of noninfectious diseases such as diabetes, cancer, or anemia. The findings also reveal that the number of health-care professionals and hospital beds per capita declined in provinces that received large refugee inflows. This study also documents a decrease in native children's probability of being fully vaccinated in provinces that received large refugee inflows. Although contact with potentially infected refugees may increase disease spread among natives, the migration-induced supply constraints in health-care access may also worsen health outcomes in host countries.