This study aims to examine challenge demands as the mediator in the relationship between future time perspective (FTP) and work engagement. Based on the Conservation of Resources (CoR) theory, we expected that personal resource as manifested by FTP would increase challenge demands, which in turn would increase work engagement. Data were collected from convenience samples of middle school teachers (N = 200) and were tested using regression analysis. Results showed that challenge demands mediated the relation between FTP and work engagement (β= .39, SE= .08, 95% CI [.24; .55]). Specifically, teachers with high FTP perceived their workload and responsibility as challenging, which increased their engagement in their work. Our findings contribute to the literature by showing that demands can turn into positive outcomes if they are considered as challenges, and that challenge demand serves as an underlying mechanism of the association between FTP and work engagement.