(FORTUNE Magazine) – This looks like a case of the pot calling the corporate kettle black. Last month the Teamsters released a study titled "America's Least Valuable Directors," in which several high-profile corporate directors were strongly criticized. Is the irony lost on anyone? America's most notorious union has anointed itself an arbiter of governance.

Targets of the study, which include former Defense Secretary Frank Carlucci and power lawyer Vernon Jordan, were dressed down for failings such as poor attendance at board meetings, serving on too many boards, and conflicts of interest. Some of the Teamsters' criticisms have merit--governance experts say that being on more than five boards may be too much. Nonetheless, it's remarkable that the Teamsters--even the new and improved Teamsters--would embark on this endeavor in the first place.

The International Brotherhood of Teamsters has been trying to clean up its act since 1989, after settling a major racketeering suit with the Feds. Ron Carey, a former United Parcel Service driver, was heralded as a Mr. Clean when he became the first democratically elected Teamsters president in 1992. Three of his predecessors, including Jimmy Hoffa, were convicted of federal charges. But Carey too has been investigated for allegations of mob connections, though unlike his predecessors, he's been exonerated. Still, the Teamsters might not be quite ready to slap a halo over their logo.

Just ask Graef Crystal, the executive-pay expert. Crystal says his research data incorporated in the study were used inappropriately. Crystal says he's been fielding angry calls by CEOs attacked in the study, including Richard Morrow (former CEO of Amoco) and Douglas Yearley (CEO of Phelps Dodge).

As for Carlucci, the Teamsters criticized him for sitting on 14 boards. Says Carlucci: "I don't want to dignify the report by responding." But Vernon Jordan, who was a member of the Teamsters when he drove a bus for the Chicago Transit Authority in the 1950s, will. He was cited for excessive absences, overcommitting himself on too many boards, and representing some of the companies for which he serves as director. "I was ill in 1994," he says explaining the absences.

As for alleged conflicts of interest, Jordan says the practice is neither "illegal nor unconstitutional" and is disclosable in a company's proxy. Jordan planned to sit down with the Teamsters to discuss the report.

Ironically, if Carey were held to rigorous standards of financial performance, he might be out of a job. Since he took office in 1992, union assets plunged from $154 million to $7 million in 1994, due in part to increased payouts of strike benefits and generous pensions to retired union officials, granted before Carey's tenure.

--Suzanne Barlyn