QPR FC (@QPRFC) January 6, 2015
The 27-year-old will play at Loftus Road until the end of the season, despite only arriving at Upton Park in the summer and impressing when given the chance.
The Argentine has made eight appearances for West Ham this season, scoring two goals and providing one assist in the league to date.
He has netted against Everton and Crystal Palace and his eye for goal will come in very handy for a QPR side desperate to climb further up the table in the second half of the campaign.
Zarate has scored 80 goals in his club career and QPR manager Harry Redknapp will be hoping he can form an effective partnership with the club's current top-scorer Charlie Austin.