Dexter Blackstock claimed the opener for the visitors on 14 minutes, with Michael Turner levelling the score for the Tigers in injury-time.
QPR took the lead in controversial circumstances as Damien Delaney survived a handball appeal on the edge of his own box and played in a ball to Hogan Ephraim.
He raced down the left and fired a cross into Hull's penalty area which Wayne Brown turned towards his own goal, forcing Boaz Myhill to turn the ball on to the post, allowing Blackstock to race in and scramble the ball over the line to put the visitors ahead.
Andy Dawson nearly had Hull back on level terms midway through the half, but his curling free-kick from 20 yards was well tipped over the bar by keeper Lee Camp.
Fraizer Campbell created a chance for himself moments later, but his turn and shot from 12 yards saw the ball fly into the sidenetting.
Campbell had another chance towards the end of the game as Claeb Folan teed him up for a header on the edge of the six-yard box, but the Manchester United loanee couldn't get enough power behind the ball as Camp comfortably palmed his effort away.
Hull did grab the equaliser in injury time as Folan raced down the right and played in a neat cross towards Turner, who buried the ball into the back of the net from close range.
Campbell had a chance to win the game for Hull moments later but his weak effort from eight yards was comfortably saved by Camp.