This thesis presents research on mental well-being of veterinary professionals at the beginning of their professional career. It aims to assess the prevalence of burnout and work engagement and to identify its work and person related antecedents in this specific group of professionals. Additionally the research described in this thesis aims for a greater understanding of the role of personal resources (i.e. aspects of the self that are related to resilience and to an individual’s perception of his ability to control the environment successfully) in mental well-being. It describes the development of a tailor-made questionnaire, theoretically based on the Job Demands-Resources (JD-R) model. According to this model job characteristics that determine employee well-being can be divided into two categories namely job demands and job resources. The questionnaire aims to identify job demands, job resources and personal resources that determine employee well-being in this specific group. Assessment of the prevalence of exhaustion, cynicism (being two dimensions of burnout) and work engagement among all veterinarians who graduated in the Netherlands between 1999 and 2009, revealed that, when compared to a random sample of the Dutch working population, the results were not very alarming. Fourteen percent of the respondents appeared to suffer from burnout and fifteen percent could be classified as being highly engaged. Men rated themselves as less exhausted and more engaged than women. The results revealed that, in line with assumptions of the JD-R model, job demands and job resources could explain levels of exhaustion and cynicism among veterinarians. Work engagement was explained best by resources, primarily job resources and to some lesser extent also by personal resources. The analyses also revealed differences between men and women in the importance of various job demands, job resources and personal resources in explaining burnout and engagement in young veterinary professionals. Subsequently, the role of three personal resources (i.e., proactive behaviour, reflective behaviour and self-efficacy) in the JD-R model was analyzed. It was hypothesized and confirmed that job- and personal resources would be the most important predictors of extra-role performance through their relationship with work engagement, and that personal resources mediate the positive relationship between job resources and engagement. These results show that interventions aimed at the development of personal resources might be useful in improving mental well-being. The final study aimed to investigate whether and how such an intervention altered participants’ personal resources and whether and how a possible alteration of personal resources related to participants’ job resources and work engagement. The results showed that the intervention was successful in increasing some of participants’ personal resources such as reflective behaviour, proactive behaviour and self efficacy, and that, according to the participants, increased personal resources affected their job resources. The results of this thesis contribute to the understanding of how aspects of the work environment and personal characteristics affect mental well-being of recently graduated (veterinary) professionals.