To evaluate whether mortality in immigrants in the region of Madrid (Spain) differs from mortality in Spanish in-country migrants. Analyses of mortality in men aged 20 to 64 years residing in Madrid were conducted, using data from the municipal population register and the cause of death register for the period 2000 through 2004. Mortality rate ratios were used to compare mortality in immigrants from different parts of the world with mortality in men residing in Madrid who were born in other regions in Spain. After adjustment was made for age and per capita income of the area of residence, the highest mortality rate ratio for the leading causes of death by disease category was observed in immigrants from sub-Saharan Africa and the lowest in those from South America and Asia. In immigrants from Western countries and from North Africa, the mortality rate ratios for most of the diseases studied did not differ significantly from those of Spanish in-country migrants. In general, the mortality rate ratios for external causes of death were higher than 1, and they were very high for mortality from homicide. Mortality from the leading causes of death in immigrants shows important heterogeneity depending on the place of origin and, with some exceptions, shows a pattern similar to that observed in studies carried out in other wealthy countries.