Abstract: With information collected from samples of health care professionals (practicing physicians and pharmacists), and against a back cloth of differing theoretical prognostications, this paper examines the nature and determinants of middle class political ideology in Ontario, Canada. We find significant variations in ideological belief within the professional middle-class. Structural, work related factors were the most important source of attitudes about the distribution of wealth, whereas gender, and other background variables, explained more of the variation in beliefs about welfare and equity policies. The findings are then discussed in terms of: theories of the new middle class; gender and politics; and the composition of political ideology. Resume: Grace aux renseignements provenant d'un echantillon de professionnels de la sante (medecins praticiens et pharmaciens), et sur une toile de fond de pronostications theoriques divergentes, l'auteure de cet article examine la nature et les facteurs determinants de l'ideologie politique de la classe moyenneen Ontario, au Canada. Elle constate qu'il existe des ecarts importants dans les opinions ideologiques au sein professionnels de la classe moyenne. Les facteurs lies au travail et d'ordre structural representaient la plus grande source d'attitudes au sujet de la repartition des richesses tandis que les sexes et les autres variables d'origine expliquaient davantage les ecarts d'opinions sur le bien-etre et les politiques d'equite. Les resultats sont discutes en termes de theories de la nouvelle classe moyenne, de sexe et politique et de composition de l'ideologie politique. Introduction: Thinking about the Middle Class Currently there is no shortage of scholars willing to proclaim that class, both as a concept and as an influence on political events, is dead or, at the very least, in need of major resuscitation (Clark and Lipset, 1991; Clark, Lipset and Rempel, 1993; Pahl, 1993; Grusky and Sorensen, 1998). The general tenor of the argument is that under conditions of 'post modernism' or 'post industrialism,' peoples' interests and identities are no longer anchored in occupational or economic activity. This is evidenced by a decline in class voting and electoral behaviour that corresponds less and less readily to the traditional polarity of the 'left-right' ideological dimension. 'Class,' it is suggested, has been swept away with the rise of 'post-material values' (Inglehart, 1977; 1990). However, amidst these claims, there is, ironically, evidence of a counter trend: growing interest in the nature of one group hitherto neglected in studies of class formation -- the middle class. Indeed, among students of social stratification not necessarily persuaded that class has become an irrelevance, the middle class is now receiving more attention than it ever did in the past. There is little doubt that this development is attributable to its growing size and diversity (Savage et. al., 1992; Butler and Savage, 1995; Langford, 1996). In contrast to a contracting manual working class, the focus of most post war debates about the changing class structure, there has been a huge expansion of professional and managerial positions -- core jobs in any body's classification of the middle class -- over the past two or three decades (Cuneo, 1983; Myles, 1988; Statistics Canada, 1988; Clement and Myles, 1994). However, recognition that the professions and management are key elements in its conceptualization does not imply agreement about the nature of the contemporary middle class. Indeed, recent exercises in re-mapping the middle class highlight distinctions, as well as commonalities, between its two principle occupational components (Goldthorpel982; Torstendahl, and Burrage, 1990). Moreover, debate about the modern middle class is not restricted to its structural determinants: there is a parallel dialogue about its political role and ideological tendencies. …