Child welfare organizations are increasingly concerned with challenges emerging from the assessment of social workers' dissatisfaction. This type of service represents the work area where social workers are at greater risk of burnout. Although several studies account for high social workers' burnout scores, they do not systematically dwell upon its sources and roots. In addition, scholars point out that a considerable number of work related issues may be perceived both as a source of dissatisfaction and satisfaction. We assume that there is a need to deepen the understanding of how dissatisfaction's sources may exert an impact on both personal job satisfaction and professional self-efficacy, which are positively associated with well-being at work. The present mixed-method research has two aims: (1) the extensive exploration, applying qualitative methodology, of the perceived sources of dissatisfaction; (2) the attempt to identify the extent to which those sources predict job satisfaction and professional self-efficacy. It is our purpose to further explore which differences emerge by age. The research involved child welfare workers, that is, SWs employed in public child welfare agencies in the North East of Italy. Results show the predominant role of interpersonal trust and mutual respect, as main predictors of both professional self-efficacy and job satisfaction. Practical implications of findings are discussed.