We investigated the associations of individual's compassion for others with his/her affective and cognitive well-being over a long-term follow-up. We used data from the prospective Young Finns Study (N=1312-1699) between 1997-2012. High compassion was related to higher indicators of affective well-being: higher positive affect (B=0.221, p<.001), lower negative affect (B=-0.358, p<.001), and total score of affective well-being (the relationship of positive versus negative affect) (B=0.345, p<.001). Moreover, high compassion was associated with higher indicators of cognitive well-being: higher social support (B=0.194, p<.001), life satisfaction (B=0.149, p<.001), subjective health (B=0.094, p<.001), optimism (B=0.307, p<.001), and total score of cognitive well-being (B=0.265, p<.001). Longitudinal analyses showed that high compassion predicted higher affective well-being over a 15-year follow-up (B=0.361, p<.001) and higher social support over a 10-year follow-up (B=0.230, p<.001). Finally, compassion was more likely to predict well-being (B=[-0.076; 0.090]) than vice versa, even though the predictive relationships were rather modest by magnitude.