BackgroundTransitioning into a new professional role is challenging. Unfortunately, little is currently known about how to reduce experiences of stress among new professionals. The socialization processes role clarity, task mastery, and social acceptance are assumed to reduce experiences of stress as they mediate new professionals’ acquisition of knowledge, skills, attitudes, and behaviors. However, little prospective data is available on the actual effect of the processes on stress. ObjectivesTo prospectively investigate how the socialization processes relate to experiences of stress among new nurses during the first three months of professional working life. Specifically, to investigate development over time, as well as how episodes of increased or decreased levels of the socialization processes relate to concurrent levels of stress. The general purpose of this investigation was to examine the suitability of the socialization processes as targets of an intervention seeking to reduce stress among new professionals. DesignAn intensive longitudinal study with weekly data collections over three months. Participants264 newly graduated Swedish nurses who started their first job during the period of the study. MethodsThe participants were followed prospectively during 14 consecutive weeks after their professional entry. Data on stress (Stress and Energy Questionnaire), role clarity (General Questionnaire for Psychological and Social Factors at Work), task mastery, and social acceptance (Needs Satisfaction and Frustration Scale) were collected weekly using digital surveys (mean response rate 82.7%). Data was analyzed using a multilevel model for intensive longitudinal data. ResultsFor the typical nurse, stress decreased by 0.13 units per month, role clarity and task mastery increased by 0.08 and 0.05 units, and social acceptance decreased by 0.08 units. In addition, the slopes of 95 percent of the new nurses varied within 1.18 (stress), 0.72 (role clarity), 0.44 (task mastery), and 0.86 (social acceptance) units of the typical nurse. Most importantly, when the new nurses experienced higher levels of task mastery, role clarity, and social acceptance, they experienced lower levels of stress (within-person parameter estimates: task mastery −0.40, p = .001; role clarity −0.34, p = .001; and social acceptance −0.33, p = .001). ConclusionsSupporting the development of the socialization processes could be one theoretically based strategy to reduce levels of stress among new nurses. As stress among new professionals is not unique to the nursing profession, and the processes are considered important mediators of new professionals’ adaptation in general, the results from this study should likely be generalizable to other professions.