[영문]Using longitudinal data from Indonesia and drawing on relevant literature?on the stress process, social support, and migrant assimilation?this study examines the consequences of rural-to-urban labour migration for mental health (as measured by depressive symptoms) and risk behaviours (as measured by smoking). The study addresses two analytic difficulties facing previous studies?the choice of an appropriate comparison group and selection bias. The results demonstrate that migration imposes considerable costs on mental health and encourages higher levels of smoking, and that the effects differ between women and men: female migrants tend to internalize the stress experienced in migration and display depressive symptoms, whereas male migrants tend to externalize various stressors by smoking more cigarettes if they already smoke though not by starting smoking. The negative impacts of migration are mitigated by family-level social support and a high degree of migrant assimilation.