40 year old Magilton has signed a two year contract with the London club. and has returned to management quickly following his departure as Town boss on 22nd April.
Confirming the news, Chairman, Flavio Briatore told the QPR Website: "We had an incredibly high number of applicants, but Jim was the stand-out candidate for the role.
"We sat down with him on four separate occasions over the last month to discuss our goals and ambitions and he has really impressed myself, Mr Ecclestone, Mr Mittal and Mr Bhatia with his knowledge, understanding and passion for football.
"He did a very good job at Ipswich Town, playing some fine, attacking football, and he has great ambition to achieve in this next chapter of his managerial career. We are all really looking forward to working with him."
Speaking of his appointment, Magilton added: "I'm really looking forward to the challenge of managing this great Football Club.
"The Board are highly ambitious, but they are very realistic at the same time. I have huge ambitions to achieve as a Manager though, and our aim is to keep progressing, year after year.
"There is a very strong group of players at the Club and with one or two additions over the summer, we can expect to be in a position to drastically improve upon the eleventh place finish secured last season."
Magilton replaces former QPR boss Paulo Sousa, who was sacked due to a poor run of displays in the 2008/9 Coca-Cola Championship season.