Epidemiological studies among migrant ethnic groups are potentially important as a way to provide insight into the relative importance of genetic, cultural, and socio-economic factors in the etiology of substance use disorders. This paper summarizes prior United Kingdom studies of the prevalence of substance-use associated problems in different ethnic groups before analysing trends in recent mortality data by country of birth. On this evidence, rates of alcohol-related mortality may be marginally higher for those born in the Caribbean than for the native British, but are substantially raised for those born in Ireland and the Indian subcontinent. There is some evidence that rates for the Caribbean and possibly the Irish groups have risen more rapidly than for the national population over a 12-year period. These differences in mortality rates seem to have arisen for complex reasons.