December was the first month since the U.S.-led invasion of Iraq nearly seven years ago in which no U.S. forces died in combat in the country.
Gen. Ray Odierno called it a significant milestone and said it speaks to how the violence in Iraq has diminished. Odierno is the commanding general in Iraq.
There were three U.S. troops who died in December as a result of non-combat related incidents.
According to an Associated Press count, 149 U.S. troops died in Iraq in 2009. That includes combat-related deaths and those not related to fighting.
That's the lowest number of U.S. deaths for a year since the Iraq war began in 2003.