Rising inequality and polarization of employment earnings have been clearly documented in Canada and most other developed economies in the 1990s. Following a critical discussion of the use of the Cini coefficient as a measure of inequality in geography, the level of inequality and social polarization of household incomes at the census tract level is assessed for Canada's 22 largest Census Metropolitan Areas. The distribution of household income among metropolitan census tracts is generally becoming more unequal. In addition, the proportion of households in middle-income census tracts is declining in most metropolitan centres, lending further support to arguments that Canada's middle class is in decline.