According to a press release from the FIM, anti-doping control testing was carried out during the Grand Prix weekend at Suzuka, Japan. All the tested riders passed the test, with negative results for banned substances.

Those tested included 125cc riders Masao Azuma of Japan and Manuel Poggialli of Spain, along with 500cc riders Valentino Rossi of Italy, Kenny Roberts of the USA, and Shinya Nakano of Japan.