The 48-year-old succeeds Neil Warnock, who lost his job on Sunday night after Rangers slumped to within a point of the Barclays Premier League relegation zone.
Hughes appeared already to have been earmarked as Warnock's replacement, with the former Manchester City and Wales boss commencing formal talks with QPR on Monday.
Hughes quit Fulham at the end of last season after less than a year in charge, suggesting the club's ambitions did not match his own.
He therefore sought assurances on that front from QPR before agreeing to join the npower Championship winners, who were taken over earlier this season by Malaysian tycoon Tony Fernandes.
Reports suggest Fernandes is ready to bankroll a January recruitment drive which could see between ?20million-?30million of new talent arrive at Loftus Road, with plans for a new 30,000 seater stadium also in the pipeline.
Hughes, who will take charge of first-team training on Tuesday afternoon before being formally unveiled on Wednesday, told the club's official website, www.qpr.co.uk: "It's a great feeling to be back in football and to be the manager of QPR.
"I'm fully aware of the challenge in the short and long term and I am genuinely excited about the ambition of the owners.
"Nobody can doubt the history of this great football club and the passion of its fantastically loyal supporters.
"Now the immediate priority is to consolidate our place in the Barclays Premier League, but beyond that, the future is very bright and fills me with great enthusiasm."
Source: PA
Source: PA