Aims This study identified clinical nurses' awareness of emergency codes and disaster nursing competencies and investigated the relationships between these variables. Background Nurses are on the front lines of disaster and emergency response; however, they report not feeling confident about their disaster preparedness. Methods Participants included 234 nurses working at a general hospital in Korea. Emergency code awareness was measured by recognition of and self‐confidence in eight emergency codes, and disaster nursing competencies were measured using the Disaster Nursing Preparedness Response Competency Scale. Data were collected from 17 to 23 October 2019. Results The recognition rate of emergency codes was 87.4%, whereas the level of self‐confidence was 3.30 out of 5. Nurses scored 2.98 out of 5 on disaster preparedness competencies and 3.37 out of 5 on disaster response competencies. Emergency code recognition was positively correlated with self‐confidence and disaster nursing competencies (p < .05). Conclusion Higher recognition of emergency codes among clinical nurses was associated with higher self‐confidence and disaster nursing competencies. Further studies need to develop strategies to improve nurses' awareness and confidence concerning emergency codes. Implications for Nursing Management Nurse managers should pay attention to provide more opportunities for disaster education to improve nurses' self‐confidence and disaster nursing competencies.