Purpose: This study aimed to compare the value congruence of nurse-patient assignment (NPA) with work performance in the neonatal intensive care unit (NICU). Methods: Data were collected with 30-items on factors that affect NPA and 17-items on work performance. Two questionnaire surveys each were conducted with 79 nurses from the NICU. The difference between expectations and actual experience on NPA were analyzed, and the effects of NPA on work performance and overtimes were investigated. The collected data were analyzed with a paired t-test, analysis of variance, and Pearson’s correlation coefficients using the SPSS software version 20.0. Results: The NPA criteria were surveyed with 30 items, with 13 patient-related, and 17 nurse-related. The validity of the tool was S-CVI .95 and the reliability (Cronbach’s ⍺) was .942. There were significant differences based on age (F=3.69, p=.029) and caring for patients on an artificial ventilator (t=2.55, p=.013). The higher the patient-related actual assignment score, the higher the nurse-related actual assignment score (r=.68, p<.001) and work performance (r=.48, p<.001). As the nurse-related actual assignment score increased, work performance also increased significantly (r=.36, p=.001). Conclusion It was confirmed that the value congruence of NPA is positively correlated with work performance.