Using the Conservation of Resources Theory and the Self-Determination Theory1-3 as theoretical frameworks, a model for this study was tested, which considers firefighters' autonomous motivation, work-family conflict, and well-being. The hypothesized model was tested using a sample of 201 firefighters from the Special Civil Protection Force in Portugal. Results revealed that autonomous work motivation was significantly related to both work-family conflict and satisfaction with life. In addition, work-family conflict was negatively related to satisfaction with life. More interestingly, the results showed that work-family conflict acted as a mechanism that helped to explain the relationship between autonomous motivation and satisfaction with life. These results underline the importance of understanding the mechanisms through which higher satisfaction with life occurs, with a view to the creation of appropriate -interventions.