Mr Thorpe, who is suffering from Parkinson's Disease, made what was believed to be his first conference appearance for nearly 20 years.
He came to hear Paddy Ashdown's speech and took his seat in the auditorium at Eastbourne shortly before lunchtime.
He rose to his feet as he was introduced by the platform and clasped his hands together above his head to acknowledge the cheers of delegates, some of them giving him a standing ovation.
The former Liberal leader nodded and applauded with others through Mr Ashdown's speech and rose to his feet with the rest of those in the hall at the end.
Mr Thorpe stood down as Liberal leader in 1976 after a series of allegations about his private life. He was acquitted at the Old Bailey in 1979 after being charged with conspiracy to murder.
Mr Thorpe appeared briefly on the campaign trail with Mr Ashdown in the South West of England in 1992, but he has made few political appearances since his acquittal.
A spokesman for Mr Ashdown said: "The party had a long, hard climb back from the wilderness years in the 1940s and 1950s and the contribution of Jo Grimond, Jeremy Thorpe and David (now Lord) Steel to that climb back has been immense.
"Jeremy Thorpe's leadership at that time was tremendously inspirational and so the party is very pleased to see him here."Reuse content