Romeo Mathieu CM (1917 – April 1989) was a Canadian trade unionist, progressive political activist, and leading solidarity builder for the Quebec labour movement.

[2] One day in 1938, while taking a lunch break from his job in the credit department of a Montreal store, a curious, young Romeo Mathieu dropped into a union meeting, and listened to an organizer from the garment workers.

TLC president Percy Bengough took special notice of Mathieu and recommended him to lead the federation's nascent organizing strategy, and corresponding campaign, for packinghouse workers.

Unlike other labour federations in the province, the FTQ kept its distance from the Maurice Duplessis government, took some militant stands – in keeping with its industrial tendencies – like the Murdochville Strike in 1957, and, eventually, supported the New Democratic Party of Canada, once it was founded in 1961.

[6][7][8] In the political arena, and in the leading intellectual and social movements of his day, Mathieu joined other young activist – such as Pierre Trudeau, Gérard Pelletier, Jean Marchand, Philippe Vaillancourt, Jean-Paul Lefebvre, and René Lévesque – in pushing for the fall of the Maurice Duplessis regime, and the rise of the Quiet Revolution, which began in the 1960s and left an indelible impact on Quebec.

"[10] In keeping with Mathieu's lifelong commitment to the "One industry, one union" concept, he played a pivotal role in the merger between the United Packinghouse Workers of America and the Amalgamated Meat Cutters and Butcher Workmen of North America (AMCBW) in 1968, creating the Canadian Food and Allied Workers (CFAW) in Canada (for internal political reasons); however, in the United States UPWA ceased to exist as a brand, and its members became members of the AMCBW.

Following the merger in Canada, the CFAW was led by the indefatigable Fred Dowling as its leader, and Mathieu serving as the obvious second-in-command and heir apparent.

This time with the creation of the United Food and Commercial Workers International Union in 1979, which, in Quebec, would have relied upon Romeo's very seasoned and sage hand leading the way.

From 1979 until his retirement in 1983, Mathieu served the UFCW as an international vice-president, and as the director of region 18, which included all of the new union's Canadian members who once belonged the Amalgamated Meat Cutters.