Macheda has struggled to make an impact at Old Trafford after scoring a famous debut goal against Aston Villa as a 17-year-old that helped secure the Premier League title in 2009.
Loan spells at Sampdoria and QPR have both proved disappointing and now the Italian is looking to kick-start his career in Germany. "I have followed the Bundesliga and naturally know about Stuttgart," Macheda told www.manutd.com.
"I am glad that I can now play for the club.
"For me, it is about getting to know the team and what I can bring because we have a lot of interesting games in three different competitions in front of us."