The number of wounded in September was the highest since the battle for control of Fallujah in November 2004, the Washington Post reported in a story based on Department of Defence data.
Last month's casualties were also the fourth highest since the US- led invasion of in March 2003.
An additional 300 troops were wounded in the first week of October, bringing the total number of US wounded in the conflict to 20,000. Nearly half of the wounded have been able to return to service, the report said.
The newspaper attributed the rising casualty rate to US attempts to halt the upsurge of sectarian violence in Iraq.
Though the public tends to focus on the deaths of 2,700 troops in the country, the number of wounded can be a more precise measurement of how fierce the conflict is, the report said. Medical advances and protective gear have saved the lives of many soldiers who may have died in earlier conflicts.