The redesign, which features a new masthead, will be unveiled in the magazine's next issue tomorrow (7 October), with footballer Joey Barton on its cover.
Sport has maintained a steady circulation since its 2006 launch, with an ABC figure for January to June this year of 306,217 copies.
But competing men’s "freemium" magazine ShortList, which launched a year later in 2007, recorded an average circulation of 523,665 for the same period.
Sport magazine was bought by UTV in May 2009, after the magazine's French parent company, Sport Media & Strategie, went into administration.
A month after the acquisition, UTV merged TalkSport and Sport magazine's sales teams to create new division UTV Pitch.
Simon Caney, editor of Sport magazine, said: "We were the first mass-distribution free magazine in the market when we launched back in 2006, and this heralds a new era for us.
"We wanted the masthead to reflect the magazine with a feeling of quality and authority, and inside the mag, art editor John Mahood has introduced a new, fresher look.
Sport magazine’s first iPad edition had been due to launch in August, but will now be released later this month.
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