Traditionally, most of the research on occupational burnout has focused on organizational stressors, such as workload and time pressure, and has overlooked the emotional nature of customer service work and its effect on burnout. This study was designed to examine the effects of individuals' affective traits (i.e., dispositional affectivity and emotional intelligence) and affective states (i.e., emotions experienced at work) on burnout. The main hypothesis of this study was that emotional intelligence acts as a moderator in the relationship between negative emotions felt by employees during their interactions with clients and emotional exhaustion. A total of 137 service sector employees rated the extent to which they felt four positive emotions (i.e., contentment, enthusiasm, joy, and liking) and four negative emotions (i.e., irritation, annoyance, antipathy, and anger) while interacting with clients. The results indicated that negative affectivity was signifi cantly associated with higher levels of emotional exhaustion, whereas high positive affectivity showed the reverse pattern. It was also observed that employees who declared greater intensity of negative emotions reported more symptoms of emotional exhaustion. However, as predicted, this effect was observed only among employees who were low in the trait of emotional intelligence. Negative emotions and emotional exhaustion were unrelated among employees who were high in trait emotional intelligence.