This study examines the effects of work engagement on altruistic performance and emotional exhaustion as well as the moderating effect of the positive and negative affectivity traits. Data were collected through questionnaires among a sample of 279 employees working in a variety of industries. Results indicate that positive and negative affectivity exert distinct moderating influences on the effects of the dimensions of work engagement. Positive affectivity accentuates the positive effect of physical engagement on altruistic performance and the negative effect of emotional engagement on exhaustion. Negative affectivity acts as a moderator in the relationship between emotional engagement and exhaustion such that emotional engagement considerably reduces the risk of exhaustion among individuals with high levels of negative affectivity.