This study examines leadership social characteristics and behaviour in an ethnic sub-community. These factors are thought to provide insight into the process of assimilation. The Winnipeg Jewish community is the ethnic sub-community and the Winnipeg community is the dominant community of this research. It is based on personal interviews with forty-six leaders of the Winnipeg Jewish community. It hypothesizes that the leaders of the Winnipeg Jewish community will be high in socio-economic status and that their patterns of behaviour will illustrate that leaders fall into a designated typology. The patterns of behaviour are investigated by examining their participation in the associations and institutions of the two communities and their social interaction with people in either one or the other community. The writer contends that when this differential participation and social interaction occurs, it has consequences for the ethnic group in that assimilation can be seen to be taking place. The significant variables are prestige, income and associational participation. When these variables are processed for correlation the results show that there is support for the hypothesis that the leaders of the Jewish community are high in prestige and income. The findings also suggest that there is some support for the hypothesis that the Jewish leaders do differ by type. Finally, the results indicate support for the hypothesis that a particular type of Jewish leader does participate in the associations of the Winnipeg dominant community to the extent that assimilation is taking place.