From 2008 until his decision not to run in 2015, the riding's parliamentary seat was held by Liberal MP Frank Valeriote. Valeriote had announced his intention to retire on November 15, 2014.
A so-called "robocall" or voter suppression scandal occurred in this riding during the 2011 federal election, when hundreds of Guelph voters who were opposition supporters received automated calls (robocalls) claiming to be from Elections Canada on election day, May 2, 2011; these calls directed them to the wrong polling stations. While reports of such calls were also alleged in five other ridings, later described as election fraud by a Federal Court judge, there was insufficient evidence to support charges in those ridings. The "robocall" incidents were referred to as the "Pierre Poutine" scandal because a cellphone in the affair was registered to a fictitious Pierre Poutine of Separatist Street in Joliette, Que.
One June 2, 2014 Michael Sona, the former director of communications for the Progressive Conservative candidate in the Guelph (Ontario) riding was charged with "wilfully preventing or endeavouring to prevent an elector from voting". Sona was found guilty on November 14, 2014  and was sentenced to nine months in jail plus twelve months of probation. During the trial, Justice Hearn agreed with the Crown allegation  that Sona had likely not acted alone. Sona was subsequently (Dec. 1, 2014) released from the Maplehurst Correctional Complex on bail after serving twelve days, pending his appeal of the sentence. However, he did not appeal the conviction.
Based on another incident during the 2011 federal election campaign, Liberal MP Frank Valeriote’s riding association was fined by the Canadian Radio-television and Telecommunications Commission for violations of the Unsolicited Telecommunications Rules. As reported by the National Post, this fine was based on a robocall message that anonymously attacked the Conservative opponent’s position on abortion. The call failed to identify its originator and did not give a callback number, according to the National Post article. Under a settlement agreement with Valeriote, the CRTC assessed a $4,900 fine.
The Liberal candidate in the 2015 federal election in the Guelph riding was Lloyd Longfield who was previously president of the Guelph Chamber of Commerce. Longfield was elected on October 19, 2015 with nearly 50 per cent of the popular vote, more than 15,000 votes ahead of the Conservative candidate Gloria Kovach.
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.