The 82nd edition features Mercedes' revamped A-Class and Ford's new B-Max family compact.
Fiat is launching a longer version of its bestselling Fiat 500 and Toyota is unveiling a more aggressive look for its Yaris hybrid.
Former governor of Californa Arnold Schwarzenegger was among the first on Thursday to visit the event that runs March 8-18.
Organizers expect about 700,000 people to visit the show on what is considered neutral ground by Europe's fiercely competitive car companies.
Automakers in Europe are struggling with the economic downturn still gripping much of the continent.
Geneva Auto Show: http:www.salon-auto.ch/en/