The automaker later said he was "recovering well".
Krueger, who fell on his back as he stumbled backward just before starting his presentation about the company's new line-up, was helped off the stage by staff.
BMW's presentation was the first in a series of press conferences lined up by various automakers for the day.
Initially staff at the stage played down the incident, but later the company in a statement said Krueger had experienced "dizziness" and his health was stable.
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As a result, the press conference was cancelled so that Krueger could be examined by a doctor, it added.
"Krueger's health is stable and he is recovering well," the company added.
It is understood that the 49-year-old Krueger hasn't been feeling well but decided to go ahead with the presentation. He had recently been travelling a lot.
Krueger had assumed role at the helm of BMW earlier this year.