The cuts, which will be made across the publisher's 32 newspapers, were first hinted at in March in response to falling advertising revenues.
CEO Tony Ridder said that advertising revenues have continued to fall, with April and May's figures down 8.6%. He added that June revenues look likely to be the same. For the year to date, ad revenues have fallen 5.1%.
The company believes it might miss its earlier target of profit growth between 20% and 30%, however earnings per share should be in line with analysts' consensus estimate of $3.29 (£2.35).
Knight Ridder publishes the San Jose Mercury News, the paper at the heart of Silicon Valley, and the Miami Herald.