Guelph riding was created in 1976 from parts of Halton—Wentworth, Wellington and Wellington—Grey ridings. It consisted initially of the Townships of Eramosa, Guelph, Pilkington and Puslinch and the City of Guelph in the County of Wellington.
The electoral district was abolished in 1987 when it was merged into Guelph—Wellington riding, adding Erin to the existing boundaries. In 1996, Erin and Pilkington was removed from the riding.
In 2003, a new riding of Guelph was created again, consisting solely of the City of Guelph.
In 2008, the election in Guelph was a four-way one between the NDP, Greens, the Tories and the Liberals, who came out on top. The NDP only won a small handful of polls in the centre part of the city, which was also where the Greens did well. In fact, the Greens dominated the central part of the city. The Tories did well on the fringes of the city, mostly along the northern borders and in the far south of the city. The Liberals won the southern and northern and western parts of the city.
The call for a federal election to be held on October 14, 2008 occurred when Guelph was already in the throes of a by-election scheduled for September 8, which was intended to replace retiring Liberal MP Brenda Chamberlain. As a result of this, the by-election was cancelled, and the four major candidates running opted to represent their parties again in the federal election. They included: Frank Valeriote, a local lawyer with thorough community experience who had garnered the Liberal nomination in an upset over regionally popular Marva Wisdom; Gloria Kovach, a city councillor and former President of the Federation of Canadian Municipalities who was controversially handed the Conservative nomination after incument nominee Brent Barr was oustered; Tom King, a renowned author and Native rights activist who received several high-profile endorsements after his NDP nomination; and Mike Nagy, a long-time Green Party spokesperson.
Initially in Guelph, optimism ran high that either the NDP, Green Party, or Conservative Party could procure the seat, as many felt that the nominees might benefit from the relative unpopularity of Stéphane Dion's Liberals and the gaffes made by prior Liberal MP Brenda Chamberlain, who had failed to show up to a number of Parliamentary votes and retired before the end of her term in office. Ultimately, however, Frank Valeriote was able to narrowly garner the seat over star candidate Gloria Kovach, who lost by around three percent and decreased the margin of defeat for her party. Noteworthy, too, was the increase in the electoral returns of the Green Party, who managed to fare better than the federal NDP in Guelph for the first time, finishing with twenty-one percent of the vote - almost three times what they had received in the 2006 election. In terms of distance from winning position, Guelph was the Green Party's best result in the country in 2008.
The riding was part of the riding known as Guelph—Wellington from 1988 to 2003. It was created in 1987 to include parts of Wellington—Dufferin—Simcoe electoral districts.
Guelph—Wellington initially consisted of the City of Guelph, the Village of Erin, and the townships of Eramosa, Erin, Guelph, Pilkington and Puslinch in the County of Wellington.
In 1996, the riding was re-defined to consist of the City of Guelph and the townships of Eramosa, Guelph and Puslinch before being abolished in 2003, and split into the current electoral district and Wellington—Halton Hills electoral district.