Vegfest, which is being held in Brighton over the weekend, said stall space sold out a month before, which is the first time the event has sold out.
And the event said its website had also seen the number of hits treble.
Organiser Tim Barford said the scandal had made people think more carefully about their food.
The free two-day event at the Hove Centre attracted more than 5,000 people last year.
