A conceptual model which relates demographic, social, and economic variables to immigrant life expectancy is developed. The model accounts for the impacts of stressors and coping mechanisms involved in the adaptation of immigrants to new environments. From the conceptual model a simplified linear model was derived. The model hypothesizes that the life expectancy change for immigrants is explained by altered living conditions ('Conditions'), the support structure of an immigrant group ('Support'), the brought and acquired skills of an immigrant group ('Skills'), and the length of residence in the destination ('Time'). The model was tested with Canadian data for 1941. Empirical indices of the dimensions Support, Skills, and Time were derived from the factor analysis of the characteristics of the immigrant groups. The model was also tested in part with Australian data for 1911-21 and 1921-33. Only the variable Conditions was included in the model since other data were not available. The parameters of the equations were obtained through regression techniques. Separate analyses were conducted for males and females. A comparison was also made of the life expectancies of immigrants in Canada with those of immigrants in Australia. The variable Conditions contributed significantly in accounting for the life expectancy change for male and female immigrants in Australia and for male immigrants in Canada. For female immigrants in Canada Support was the only variable to influence life expectancy change. Support also determined, though to a lesser degree than Conditions, life expectancy change for male immigrants in Canada. The finding that the support structure influences life expectancy change, especially for females, has important policy implications. It points to the benefits of a policy of cultural pluralism as opposed to one of rapid assimilation. The significant role of the destination conditions indicates that an extensive exploration of the differences in the environmental, technological, political, social, and cultural systems of the origin and destination countries has potential for defining specific factors contributing to disease prevalence and mortality. / Graduate and Postdoctoral Studies / Graduate