Purpose : In this study, we aimed to identify the factors affecting nurses’ competency in delirium care in an intensive care unit at a tertiary general hospital. Methods : The participants were 149 nurses in the intensive care unit. Collected data were analyzed using independent t-tests, ANOVA, Sheffé test, Pearson correlations coefficients, and multiple regressions using the SPSS 28.0 program. Results : The factors that significantly influenced the participants’ competency in delirium care were delirium nursing confidence (<i>β</i>=.44, <i>p</i> <.001) and intensive care unit clinical career (<i>β</i>=.25, <i>p</i> =.002). These factors explained 32.5% of the total variance outcomes regarding the competency in delirium care (F=12.87, <i>p</i> <.001). Conclusion : The study results indicated that the higher the confidence in delirium care and the more extensive intensive care unit experience, the higher the competency in delirium care. Moreover, these results suggested that various policy strategies should be implemented to enable intensive care unit nurses to work for a long time and to develop educational programs to increase confidence in delirium care.