Led by military-appointed permanent secretary Chutima Bunyapraphasara, the bureaucrats vowed to clear corruption from their workplace and guard against new incidents as demanded by the National Council for Peace and Order.
The Commerce Ministry historically has been a lightning rod for corruption allegations, most recently during the rice-pledging scheme conceived by Yingluck Shinawatra's government.
Ms Chutima said corruption would not be tolerated at the ministry's offices in Bangkok, provinces or overseas.
"If there is an offer, we will not take it. All director-generals are instructed to implement the policy," she said. "If there is any issue about corruption, the public can report to me directly and I will take a strong effort to ensure transparency."
The ministry recruited its workers via Facebook to join the "zero corruption" pledge, as well as point out any practices or working processes vulnerable to corruption.