In their new article “Mortality in adult immigrants in the 2000s in Belgium: a test of the ‘healthy-migrant’ and the ‘migration-as-rapid-health-transition’ hypotheses” in Tropical Medicine & International Health, prof. Hadewijch Vandenheede, Didier Willaert, Hannelore De Grande, Steven Simoens and Christophe Vanroelen map out and compare all-cause and cause-specific mortality patterns by migrant background in Belgium and probe into explanations for the observed patterns, more specifically into the healthy-migrant, acculturation and the migration-as-rapid-health-transition theories. In order to do so they use individually linked Belgian census-mortality follow-up data for the period 2001–2011. The results show that first-generation immigrants have lower all-cause and chronic-disease mortality than the host population. This mortality advantage wears off with length of stay and is more marked among non-Western than Western first-generation immigrants. For example, Western and non-Western male immigrants residing 10 years or more in Belgium have a mortality rate ratio for cardiovascular disease of 0.72 (95% CI 0.66–0.78) and 0.59 (95% CI 0.53–0.66), respectively (vs host population). The pattern of infectious-disease mortality in migrants is slightly different, with rather high mortality rates in first-generation sub-Saharan Africans and rather low rates in all other immigrant groups. As for second-generation immigrants, the picture is gloomier, with a mortality disadvantage that disappears after control for socioeconomic position. The findings in the article are largely consistent with the healthy-migrant, acculturation and the migration-as-rapid-health-transition theories. The convergence of the mortality profile of second-generation immigrants towards that of the host population with similar socioeconomic position indicates the need for policies simultaneously addressing different areas of deprivation.