Aim. Diagnostic uncertainty, risk perceptions, time constraints, and pressure from resident/family members and nurses have been identified as potential barriers to reducing antibiotic prescribing in residential aged-care facilities. The current study investigated the relationship between nurses’ anxiety, clinical tolerance of uncertainty, and behaviors that favor antimicrobial initiation. Methods. A cross-sectional online survey was used to present a clinical vignette with measures of situational anxiety, clinical tolerance to uncertainty using the Physicians Reactions to Uncertainty Scale (adapted for nurses), and self-reported behavior on the Immediate Assessment and Antibiotics scale. The vignette described a hypothetical resident with a potential upper respiratory tract infection. Incremental information was provided with varying levels of symptoms, input from aged-care staff, and the availability of test results. Results. A total of 157 registered and enrolled nurses completed t