This study examines harmonious and obsessive passions as underlying psychological processes influencing the effects of task significance on performance. Using self-determination theory to account for the mediation effect, we argue that the relationship between task significance and employee performance is indirect, and harmonious and obsessive passion play a significant role as mediators. The data were collected from healthcare workers at an Indonesian government organization (N = 434) and were analyzed using the Hayes PROCESS macro. The results showed that task significance was positively and significantly correlated with harmonious passion and obsessive passion. Harmonious passion was positively and significantly correlated with performance, but obsessive passion was not correlated with performance. Furthermore, harmonious passion fully mediated the effect of task significance on performance, but obsessive passion did not mediate this relationship. The theoretical and practical implications of the findings are discussed.