Her appointment followed a board meeting of Newspaper Publishing, owner of the Independent titles. A statement said: "Ms Boycott will continue as editor of the Independent on Sunday, where she has presided over the tremendous performance of that title, which shows year-on-year circulation increases and is widely credited as being Britain's most improved newspaper in 1997."
Liam Healey, chairman of Newspaper Publishing, said the shareholders were fully committed to both titles.
Ms Boycott, who replaces Andrew Marr, has been editor of the Independent on Sunday since October 1996. She will now guide both papers across seven days.
The co-founder of Spare Rib magazine and Virago publishing, Ms Boycott also worked at the Daily Mail, the Sunday Telegraph and Harpers & Queen. In 1984, she published her autobiography, A Nice Girl Like Me.
She then became editor of Esquire magazine, where she twice won the ward for Magazine Editor of the Year.
Ms Boycott said she was "delighted and excited" by her appointment. "I look forward to working with an extremely talented team. The IoS has enjoyed considerable success in the last year. It has established a reputation as a campaigning, vibrant newspaper - qualities which I intend to bring to the daily."Reuse content