Canada is on the threshold of a major transformation in its ethnic and racial profile. Relative rates of immigration from European and non-European countries have reversed during the past 40 years. What impact has this had on the attitudes of the dominant white majority? This article provides a partial answer to this question by examining the attitudes and voting behaviour of this majority when faced with increasing concentrations of visible-minority neighbours. Attitudinal data from the 1997 and 2000 Canadian Election Studies were combined with data from the 1996 census to measure socio-economic status and the visible-minority population of the neighbourhoods occupied by survey respondents. Regression analysis reveals two different contextual effects involving the attitudes of the majority toward visible minorities. Positive attitudes towards visible minorities increase with neighbourhood socio-economic status, a finding consistent with "social identity" theory. However, positive attitudes toward racial minorities decline when the visible-minority population increases, a finding consistent with "realistic conflict" theory. Both contextual effects have implications for voting. Independent of individual characteristics, white voters are more likely to support Reform/Alliance if they live in less-educated environments or among higher numbers of visible-minority neighbours.