This investigation aims to explore the moderating role of volunteers’ age in the relation between motivations for volunteering and, respectively, satisfaction with volunteerism and emotional exhaustion. A longitudinal study was conducted with a sample of 241 Spanish healthcare volunteers. Results show that volunteers’ age moderates the relations between social motivations and satisfaction, and social motivations and volunteers’ emotional exhaustion, and also between growth motivations and satisfaction, and volunteers’ emotional exhaustion. The relationships between security motivations and satisfaction and emotional exhaustion are not moderated by age. Our findings underline that, for younger volunteers, satisfaction decreases when social motives are high, rather than low, and, in the opposite, emotional exhaustion increases when growth motives are high, rather than low. For older volunteers, instead, the only significant effect concern satisfaction, which is higher when social motives are high, rather than low.