In a memo to the staff on Monday, Lipinski said that there is no one reason for her decision, but that professionally, "this position is not the fit it once was."
Lipinski has been editor since 2001 and says she will stay on the job through Thursday. She is being replaced by Gerould W. Kern, who joined the Tribune in 1991.
Lipinski started at the Tribune as a summer intern. In 1988, she was one of three reporters awarded a Pulitzer Prize for a series of investigative stories about the Chicago City Council.
Her resignation comes two months after George De Lama, the paper's managing editor for news, announced he was leaving the Tribune after 30 years.
