The Leicester site of the printer, part of £425m Daily Mail and General Trust (DMGT), is producing the title, which has a print run of more than 50,000 copies.
The new paper is a joint venture between Iliffe News and Media and Observer Standard Newspapers.
Harmsworth is printing the Nuneaton Observer four-colour on one of its Goss HT60 presses using 45gsm standard newsprint.
The 64pp newspaper will feature an advertising/editorial split expected at 25%/75%.
The Leicester arm of Harmsworth Printing produces 35 weekly titles including The Stage and also carries out work for Archant Newspapers.
Iliffe News and Media, which already publishes the Heartland Evening News in Nuneaton, will provide the majority of the editorial content and advertising sales.
Additional support will be provided by the nearby Observer Standard operation in Coventry.
Iliffe News and Media chief executive David Fordham said: "The opportunity of joining forces with Observer Standard Newspapers in Nuneaton is an exciting one."