We apply a variant of the microeconometric decomposition methodology proposed in Bourguignon et al. (1998) to assess the relevance of various factors that affected inequality in the period 1986-1998 in the Greater Buenos Aires area. The results of the paper suggest that the small change in inequality between 1986 and 1992 was the result of mild forces that compensated each other. In contrast, between 1992 and 1998 nearly all factors played in the same direction. Changes in the returns to education and experience, changes in the endowments of unobservable factors and their returns, changes in hours of work and in labor force participation, and the transformation of the educational structure of the population have all had some role in increasing inequality in Argentina to unprecedented levels. The increase in the returns to education, changes in endowments of unobservable factors and their remunerations, and the fall in hours of work by low-income people are particularly important to explain the growth in inequality in the nineties. In contrast, although Argentina witnessed dramatic changes in the gender wage gap, the unemployment rate and the educational structure, these factors appear to have had only a mild effect on the household income distribution.Departamento de Economí