The governing body, the FIM, renamed the premier class from 500cc to MotoGP ahead of the 2002 season, though promotional use of the MotoGP name had already begun in 2000. The 990cc four-stroke rule was designed to invite fresh manufacturer investment and break the stranglehold of specialised two-stroke development. Only four factory teams — Repsol Honda, Marlboro Yamaha, Suzuki, and Aprilia — fielded the new machines from the start of the season. All satellite teams initially raced the existing 500cc two-stroke equipment.
Tyre competition also diversified in 2002. Michelin remained the dominant supplier, but Dunlop returned to the premier class, supplying Suzuki, Aprilia, Yamaha WCM, and Pramac Honda. Bridgestone entered as a new supplier to Team Roberts and Kanemoto Racing, beginning what would become a long-running tyre war at the front of the grid.
Valentino Rossi, aboard the Honda RC211V, was dominant from the opening race at Suzuka, where he won in wet conditions. He won seven consecutive races at one point and clinched the world championship at the Rio de Janeiro Grand Prix with four rounds remaining. Rossi finished the season with 355 points from 11 victories and four second-place finishes.
Max Biaggi finished second in the championship with 215 points and two race wins, including a notable victory at the Czech Republic Grand Prix at Brno where Rossi retired with tyre problems. Tohru Ukawa and Alex Barros rounded out the top four. Daijiro Kato, riding for Honda Gresini after switching from the Honda Pons team mid-season, earned Rookie of the Year honours with two podium finishes.
Kawasaki returned to world championship competition after a 20-year absence, fielding their new ZX-RR four-stroke as a wildcard in the final four rounds as preparation for a full campaign in 2003. Honda won the constructors' championship with 390 points and 14 race victories. All 16 races were won by four-stroke machinery. The two-stroke bikes managed only five podium finishes across the season, and Loris Capirossi was the leading two-stroke-only finisher, classified eighth overall.
Marco Melandri was the dominant force in the 250cc class, winning nine of the 16 races and becoming the youngest 250cc world champion at 20 years and 74 days — a record at the time. He clinched the title at the Australian Grand Prix with a margin of just 0.007 seconds over Fonsi Nieto at the finish line. Melandri finished the season with 298 points.
Nieto, who won four races including a dramatic recovery win at Portimao in wet conditions, finished second with 241 points. Roberto Rolfo and rookie Toni Elias completed the top four. Elias, who won his first race at Motegi after a last-lap battle with Melandri, was awarded Rookie of the Year in the class. Aprilia dominated the constructors' standings with 382 points and 14 race wins.
The 125cc title was decided on the final lap of the final race at Valencia. Arnaud Vincent, who had returned to Aprilia after a season with Honda, clinched the championship by finishing second to Daniel Pedrosa, ending 19 points ahead of defending champion Manuel Poggiali. Poggiali, needing a strong finish to take the title, could only manage seventh place.
Vincent finished with 273 points and five race wins. Pedrosa, in only his second season, showed exceptional promise by winning three races and finishing third in the standings. Finnish rider Mika Kallio won the Rookie of the Year award. Aprilia won the constructors' championship with 341 points.
The 2002 season established the template for the modern MotoGP era. The complete dominance of four-stroke machinery — all 16 races won by the new 990cc bikes — validated the rule change faster than many had expected, and the two-stroke machines were phased out entirely for 2003. Honda's RC211V, with its V5 cylinder configuration, set a performance benchmark that rivals spent years attempting to match. The season also began the tyre competition between Michelin, Bridgestone, and Dunlop that would characterise the following years of the championship.