The department is urging authorities nationwide, as well as security officials in the private sector, to be more vigilant.
An "Information Bulletin" sent out this week said stolen uniforms, badges and other identification from law enforcement, government or private companies could be used by terrorists who want access to sensitive sites to carry out attacks.
The report sites that several press reports this year have referred to the theft and sale over the Internet of a large number of United Parcel Service (UPS) uniforms. It also states that while these reports proved to be false, they did bring to the public's attention the potential security concerns of missing or stolen identification, uniforms, or vehicles.
But spokesman David Wray cautioned that the bulletin is simply meant to raise awareness about a potential problem. "We have no specific threats to indicate that something like this is imminent," he said.
The department studied "selected members" of law enforcement communities in five states, and it found that hundreds of official ID cards, badges, decals, uniforms and government license plates were reported stolen or lost.
Wray declined to say which states were involved or to elaborate on the specific types of items that were missing or exactly where they were missing from.
The study covered February to May of this year.
The advisory was sent to state, local and other authorities across the country. It also was distributed to contacts in the private sector, such as oil, gas and financial services companies, said Wray.
The information bulletin said a number of private companies have reported receiving suspicious inquiries about renting official delivery vehicles. It also said emergency services officials have "received unusual requests for detailed vehicle descriptions."
The bulletin said the department has no information that al Qaeda or other terrorist groups are trying to obtain official IDs or other materials.
But it is a scenario the department is concerned about, according to Wray.
"We've seen these tactics employed overseas and it's not a great leap to assume they could be employed here," he said.
The department is asking authorities to be rigorous about examining credentials and safeguarding badges, uniforms and other forms of official identification.
The Department of Homeland Security is also working on building smarter and more secure borders. They recently proposed new regulations that require advance information, in electronic format, on cargo destined to and from the United States for each mode of transportation: air, truck, rail, and sea.