Researchers have rarely considered professionals in studying organizational and work unit identifications. Professionals frequently use their identities deriving from professions to situate themselves in organizations (Ashforth, Harrison, & Corley, 2008). As professionals play increasingly important roles in organizations (Chreim, Williams, & Hinings, 2007), it seems timely to understand professionals’ identifications in the workplace. This research attempts to address this issue by examining two moderating effects of professional identities (i.e., professional status and professional identification) on how professionals develop identity in the workplace. Specifically, this research focuses on the moderating role of professional status in the relationship between perceived organizational prestige and organizational identification, and between perceived work unit prestige and work unit identification. The study also investigates the moderating role of professional identification on the impact of organizational identification on in-role and organizational citizenship behaviors, and of work unit identification on citizenship behavior towards work unit. This study collected data from nurses of three hospitals in central China. Interviews were first conducted to see whether multiple identifications exist among nurses. Survey was then administered in three time waves to test the hypotheses. Each wave lasted for three weeks. In the first wave, nurses provided information about perceived organizational prestige and perceived work unit prestige. In the second wave, nurses gave their responses to professional status, professional identification, organizational identification, and work unit identification. During the third wave, nurses answered questions on citizenship behavior towards work unit, whereas head nurses rated nurses’ in-role and organizational citizenship behaviors. iv The final sample consisted of 363 supervisor-subordinate dyads. This research found that professional status moderated the relationship between perceived work unit prestige and work unit identification. This study also found that professional identification moderated the relationship between organizational identification and in-role and organizational citizenship behaviors, and the relationship between work unit identification and citizenship behavior towards work unit. This research contributes to the literature by demonstrating how professionals’ personal identity interplays with social identity to influence group identification, and how professionals navigate their multiple identities in the workplace. Discussions are made on the study’s theoretical and practical implications, limitations, strengths, and future research directions.