This thesis argues that gender shaped the roles available to the men and women who created Winnipeg's public health system between 1882 and the 1940s. Before the First World War, Winnipeg's male-dominated health department focussed almost exclusively on sanitation and regulation. At the same time, female social reformers founded two voluntary visiting nursing organizations and pioneered school health and maternal/child health programs. Gendered ideas about appropriate roles for men and women in the public sphere established the boundaries between these two approaches to public health. Because gender is an unstable construct, this division of labour changed over time. As female-led organizations became increasingly dependent on grants from organized charity and government, their managerial practices came under the scrutiny of male bureaucrats. These professional men destabilized the previously established boundaries between civic and voluntary public health programs. Voluntary organizations lost much of their autonomy and physicians exerted increased control over the practices of visiting nurses. Finally, many programs initiated by the visiting nursing associations were taken over by the civic health department. Public health programs were also used to maintain social order and regulate individual behaviour. The programs pioneered by Winnipeg's visiting nursing associations were convenient vehicles for elite and middle class women to disseminate multiple messages to immigrant and working class women about the appropriate behaviours, attitudes, and beliefs expected of Canadian citizens. Finally, this thesis demonstrates that women's contributions to Winnipeg's public health system, although largely ignored in the standard histories, established a legacy and a pattern that shape the publicly funded system to this day. However, by 1945, lay women and professional nurses were virtually excluded from policy development within Winnipeg's public health system.