Two weeks after Peter Gethin's amazing victory at Monza, the F1 field gathered in Canada. BRM fielded five cars for the occasion Gethin being joined by regulars Jo Siffert, Howden Ganley, Helmut Marko and Canadian George Eaton. Ferrari was up to three cars again with Mario Andretti joining Jackie Ickx and Clay Regazzoni. McLaren replaced Jackie Oliver with US star Mark Donohue (although the second McLaren was owned by Roger Penske and entered in American racing dark blue). There were a variety of extra privateers including Skip Barber's Gene Mason-entered March, Alain de Cadenet's Brabham for Chris Craft and Peter Lovely in an old Lotus.

Qualifying resulted in World Champion Jackie Stewart putting his Tyrrell on pole position ahead of Jo Siffert's BRM and the second Tyrrell of François Cévert. Emerson Fittipaldi (Lotus) and Chris Amon shared the second row, while Ronnie Peterson (March), Reine Wisell (Lotus) and Donohue (McLaren) were on the third row. The Ferraris were not competitive with Ickx 12th, Andretti 13th and Regazzoni 18th.

There was a fatal accident in the Formula Ford race and the Grand Prix was delayed, and by the time the race started it was pouring with rain. Howden Ganley demolished his BRM in the warm-up period before the race and so could not make the start. At the start Stewart went into the lead with Peterson second, chased by Beltoise, Donohue, Fittipaldi, Cévert and the rest. On the third lap Graham Hill crashed his Brabham and five laps later Regazzoni did the same in his Ferrari and lucky to emerge unscathed when the car caught fire.

Stewart had a firm grip on the race while Peterson had to fight for second with Beltoise until the Frenchman crashed on lap 16. At the same time Donohue pitted for new goggles but did not lose a place. This left a huge gap between the first two and the rest. Peterson took the lead on lap 18 but on lap 31 Stewart took the lead back while they were going through backmarkers. A few moments later Peterson ran into Eaton's BRM and damaged the front of his car. This upset the balance of the car and Peterson was unable to match Stewart's pace and so the Tyrrell edged away to win by nearly 40 seconds. Donohue finished third on his F1 debut.