Background: Work engagement is defined as a positive, fulfilling, work-related state of mind characterized by vigor, dedication, and absorption. Even though volunteers at hospitals are deeply engaged in their unpaid work, there are no quick tools for measuring work engagement among these volunteers. The Ultra-short UWES-3 is a valuable research tool to measure engagement, indicating the need for its validation among volunteers.
 Several recent studies have explored the role of work engagement in volunteer work, mostly focusing on volunteers working in social and nonprofit settings. Little is known about how work engagement contributes to the well-being and quality of life of volunteers working in hospitals. Furthermore, in this context, the relationship between work engagement and burnout, referred to as a psychological syndrome of emotional exhaustion, is poorly understood.
 Objectives: The objectives of this study were to examine the factor structure of the UWES-3, and to undercover possible associations between work engagement, well-being, quality of life, and burnout among volunteers.
 Methodology: This cross-sectional study collected self-reported anonymous data from adults connected to volunteer organizations in Guadalajara, Mexico.
 Results: Confirmatory factor analysis supported the scale’s unidimensional structure. While well-being and quality of life were positively associated with work engagement, exhaustion showed the strongest negative relationship to work engagement.
 Discussion: Our results support the validity of the UWES-3 and suggest that work engagement contributes to well-being and quality of life, while exhaustion is negatively associated with work engagement. From a wider perspective, results from this study provide important insights to guide stakeholders, such as hospital administrators and volunteer organizations.
 Conclusions: Our findings support the validity of the UWES-3 among hospital volunteers, suggesting that the scale is an appropriate work engagement measure in this setting. This study provides a new understanding of the relationship between work engagement, burnout, and psychological variables among hospital volunteers.