(FORTUNE Magazine) – Fred Nahas is not your typical union activist. The 51-year-old doctor is a vascular surgeon in Somer's Point, N.J., and earns a comfortable six-figure income. His only experience with a picket line was during his residency at Temple University Hospital, when the hospital's maintenance workers went on strike. Back then he had no qualms about crossing the line.

Now, however, Nahas is leading a group of about 200 doctors in two south Jersey counties who have presented the National Labor Relations Board with a highly unusual petition (a hearing is scheduled for Dec. 8 in Philadelphia). They want Local 56 of the United Food and Commercial Workers Union--better known for organizing supermarket employees--to represent them.

Doctors have joined unions before, but this bunch is different. They're private practitioners--or independent contractors, in labor jargon. And the party with which they wish to negotiate is not their employer, in the normal sense of the word. It's AmeriHealth, a local HMO, one of several health plans from which they receive patients and collect fees.

Until now, the only doctors permitted under antitrust laws to engage in collective bargaining have been employees of hospitals or clinics. Nahas and his group are hoping to convince the NLRB that intrusive, domineering HMOs have converted them into de facto employees. In which case, says Nahas, "we should have the protections afforded by the national labor laws, one of which is the right to unionize."

Nahas accuses AmeriHealth and others of "practicing medicine without a license" and declares, "People are dying and losing limbs...because of decisions that are set forth by HMOs." (Paul Langevin, president of the New Jersey HMO Association, says, "There is no empirical evidence to demonstrate any of that." AmeriHealth chose not to respond.)

Doctor unrest isn't unique to New Jersey. Last summer the American Medical Association's House of Delegates adopted a strongly worded resolution in favor of collective bargaining. While they failed to overturn the AMA's official stance on unions ("the promise that union affiliation will provide physicians with more clout is a promise that will inevitably prove false," states an AMA policy report), the delegates did force the creation of a new AMA Division of Representation. It will represent doctors in collective bargaining with health plans, though only on noneconomic issues. Earlier, a group called the Ad Hoc Committee to Defend Health Care, based in Cambridge, Mass., circulated a widely discussed petition charging that "canons of commerce are displacing dictates of healing, trampling our profession's most sacred values." Among its endorsers are several unions.

What do the doctors want, exactly? Nahas concedes that money, benefits, and working conditions are important issues for them, as they are for all union members. But doctors know they won't get much sympathy there. What they're really after, they insist, is recapturing from insurers the power to practice medicine as they see fit. "Physicians are driven by quality of care," says Nahas. "HMOs are cost-driven. They'll do whatever they can to limit expense. So they have developed over the years a very sophisticated way of preventing care, delaying care, denying care, retrospectively refusing to pay for care."

That's the message the union is pounding home in radio and television spots that began airing locally in November.

Most experts believe Nahas and his colleagues have started a fight they can't win. Then again, who ever said organizing a union was easy? "They've got a lot of true believers," says Robert O'Brien, the attorney for Local 56. "There is a fervor that I haven't seen in years."

--David Whitford