The aim was to investigate the effects of organizational change on psychological well-being and workrelated stress by considering employees' perceptions of change. A longitudinal survey-based study with two waves over three years was conducted within an organization that underwent an administrative restructuring process resulting in a number of organizational changes. A total of 145 Italian employees (64.1% women) participated in both waves, in which the Health and Safety Executive Stress Indicator Tool (HSE) and the General Health Questionnaire (GHQ) were administered before and after organizational changes, while Perceived Organizational Change (POC) was assessed after the organizational change. Results suggest that perceived organizational change had a significant effect on risks of work-related stress and people's wellbeing after one year and a half that organizational changes occurred. These findings provide new evidence that critical situations could not be necessarily negative, since effects and outcomes strictly depend on people's mental representation of situations. The study empathizes the effect of perceptions of a specific organizational risk factor, namely organizational change, in a longitudinal design of three years.