Editorial and advertising slots across the UK's 270 commercial radio stations highlighted autism and encouraged people to respond to the survey.
Seventy-nine per cent of people who had no contact with autistic people were unaware that savant autism – made famous by Dustin Hoffman's character in Rain Man – was rare.
Director of comms and public affairs Quentin Rappoport said the results suggested the majority of people were misinformed about the condition.
'Respondents who didn't know someone with autism showed ignorance, but people who did know an autistic person also showed a lack of knowledge on fundamental points,' he said.
All respondents were told the answers to the questions they got wrong and were sent information packs. The charity hopes to conduct a similar survey next year to assess whether awareness has improved.
'From these results we know we must continue to raise awareness of the issues that affect people with autism and challenge misconceptions,' said Rappoport.