This descriptive study was undertaken to identify the degree of ethical sensitivity of staff nurses and to analyze the differences in ethical sensitivity in terms of both general and ethics-related characteristics. Participants were 236 staff nurses working in general hospitals in Korea. Ethical sensitivity was measured by means of an instrument developed by the researchers. The results showed that the mean score for the degree of ethical sensitivity was 0.71 out of a possible maximum score of 1 (range 0.30 to 0.97). For general characteristics, there was a significant difference in ethical sensitivity according to age (F (df 2233) = 3.99, P = 0.02). For characteristics related to ethics, there was a significant difference in ethical sensitivity according to attitude towards the nursing profession (F (df 4231) = 2.94, P = 0.03). It is therefore recommended that a training program reflecting these variables be developed to enhance staff nurses' ethical sensitivity.