This article introduces a psychology of economic immigration as a field complementary to but separate from research on acculturation. A theoretical model of psychological disharmony is outlined, where hard work and thrift become the crucial elements of immigrant condition. Three studies are reported. Studies 1 and 2 were conducted among Polish immigrants in Ireland. These studies addressed personality comparisons between immigrants and nonimmigrant samples (Study 1: peer observations) and immigrant self-perceived changes (Study 2). Adaptive personality changes did occur as hypothesized, particularly in the domain of conscientiousness, which regulates work-related activities. This finding was restricted in Study 2 to a prospective time frame (change measured with time flow). Study 2 introduced four lifestyles: eudaimonia, hedonism, self-sacrifice, and alienation. Prospective change in conscientiousness favored eudaimonic lifestyle, but retrospective change predicted self-sacrifice. Participants in Study 3 were Eastern Slav and Vietnamese immigrants in Poland. Based on previous work on Confucian work dynamism, it was expected that Vietnamese would demonstrate greater work involvement, eudaimonic lifestyle, and thrift, compared to Slav immigrants. These hypotheses were confirmed, showing that within the general model of immigrant adaptation, there is room for cultural differences.