ABSTRACT Background: Patient safety issues became a global health concern, especially the occurrence of avoidable complications from surgical procedures. In 2008, World Health Organization launched the Safe Surgery Saves Lives program to improve patient safety. This study aimed to investigate the relationship between compliance to surgery safety checklist and incidents among anesthesiology nurses in operation theater at Royal Prima General Hospital, Medan, North Sumatera. Subjects and Method: This study was a cross-sectional study conducted at Royal Prima General Hospital, Medan, North Sumatera, in August 2019. A sample of 25 anesthesiology nurses was selected by the total sampling. The dependent variable was incidents in the operating room. The independent variable was the compliance of anesthesiology nurses on performing surgical safety checklist. The data of nurse compliance were measured by the completeness of filling sign in, time out, and sign out surgical safety checklists. The data were analyzed by chi-square. Results: The incidents in the operating room reduced with compliance in surgical safety checklist filling, but it was not statistically significant (OR= 0.12; 95% CI= 0.01 to 1.95; p= 0.218). Conclusion: The incidents in the operating room reduce with compliance in surgical safety checklist filling, but statistically non-significant. Keywords: surgical safety checklist, incidents, operating room Correspondence: Wienaldi. Department of Public Health, Faculty of Medicine, Universitas Prima Indonesia, Medan, Indonesia. Email: [email protected]. Mobile: +6285270130535. DOI: https://doi.org/10.26911/the7thicph.05.32