Thousands of Hispanics who live near the border are taking advantage of a benefit increasingly offered by their U.S. employers: less expensive health care in Mexico.

About 160,000 workers in California -- farm laborers as well as working-class Hispanics employed at hotels, casinos, restaurants and local governments in San Diego and Imperial counties -- are getting their annual checkups and having surgery through health networks south of the border, insurers say.

The arrangement is less expensive for both employers and employees. In Mexico, health care costs are about 40 to 50 percent lower than in California, freeing some employers to offer services that they could not otherwise afford.

"It's a win-win situation for me. I'm able to offer it to everybody and my premiums went way down," said Mark Holloway, part owner of a department store in Calexico, Calif., who said he could not afford health insurance for his 50 employees until he enrolled them in a cross-border plan.

He said he could sign up four employees, each at about $100 monthly, for about the same price as one employee in a U.S. plan.

Employees have lower premiums and co-pays, typically $5, and the comfort and convenience of describing their aches and pains in Spanish to doctors who, they say, tend to take more time with them.

"The rate is good, the service is good," said David Ouzan, a city councilman in Calexico, where he is among the roughly one-third of the city's workers who use dental and medical clinics in Mexicali, just across the border. "I myself have used dentists in Mexico."

Still, the trend has generated some misgivings among physicians and consumer advocates on the U.S. side of the border. Some worry about the quality of care and lack of regulatory control in Mexico. Others say the cross-border plans represent a sad commentary on the limited access that immigrants and the working poor have to treatment in California.

They represent a "positive turn of events for cross-border health coverage . . . but are another reminder about how sick our health system is in the U.S.," said Robert K. Ross, a physician and the president of the California Endowment, a health care philanthropy.

Mexico has long been a low-cost alternative for thousands of people -- many of them uninsured -- who price-hunt among clusters of storefront clinics and small hospitals in Tijuana and Mexicali for treatment they cannot afford in the States. Some cross-border health plans have operated since at least the 1950s, when Imperial Valley farmers started offering coverage to migrant workers.

But the emergence in the last five years of cross-border HMOs, which must be licensed by the state of California, signals the growing acceptance of Mexican health networks by mainstream employers and insurers in the United States.

So far, three HMOs, two in the United States and one in Mexico, SIMNSA, are providing such care to employees of Californian companies, covering 36,000 workers and their dependents, according to figures provided by the insurers. About two-thirds of those employees are covered by the U.S. insurers Blue Shield of California and Health Net Inc. (Health Net enrollees can use clinics on either side of the border.)

Enrollees are typically Mexican citizens legally employed at U.S. companies, living either in Mexico or in the United States. Many earn only $5 to $7 per hour. But others are Mexican Americans, some of them in executive positions.

"Employers are really surprised a bit by the quality, the cleanliness," said Peter Duncan, a vice president at Blue Shield of California, whose cross-border program is called Access Baja. "Often they had visions of squalor. It isn't Cedars-Sinai. But they find that the basic quality of care is really there."

Mexican facilities that are part of HMO networks serving U.S. companies are audited by the HMOs themselves for sanitary conditions, infection-control policies and staff training levels, as required by the California Department of Managed Health Care. They are not evaluated directly by state regulators, although the state keeps the audits on file and can investigate complaints if a patient is not satisfied with the HMO's response. Physicians must be licensed in Mexico and maintain a good standing in the medical community.

Still, some medical experts are concerned about what they describe as a wide variation in quality south of the border.

Although comparing the two systems, with their differing standards and philosophies, is difficult, physicians on both sides of the border say the Mexican regulatory system is lax and that physician training is not as rigorous as in the United States. In Mexico, doctors typically need six years of schooling; in the United States, it's eight to 11 years, including college, medical school and possibly a residency.

"High quality does exist in many places," said Michael Rodriguez, a UCLA professor familiar with the border region, but "sometimes there are places that you'd wonder whether you would want to take a dog for treatment, let alone a person. . . . My guess and my hope is that HMOs are very [discriminating] who they work with."

Some consumer advocates say the audits done by HMOs are potentially a conflict of interest. And they note that when complaints are made, the state might not have the jurisdiction to investigate them thoroughly. Mexican doctors, for instance, are not subject to regulation by the Medical Board of California.

Insurers, employers and many border medical experts insist that the Mexican plans offer an acceptable level of care to a population that prefers to get its health care in Mexico, even when offered plans in California.

But for some Hispanics along the border, any plan is an improvement. They are more likely to lack heath insurance than any other demographic group, according to the National Hispanic Medical Association, and one of the draws of these cross-border plans is that they are a bargain.

Monthly premiums average about $100 for individuals and $350 for families in Blue Shield of California's Access Baja plan. By contrast, according to a 2004 survey of employers by the California Healthcare Foundation, the average monthly premium for California HMO plans was $261 for singles and $721 for families.

Most cross-border enterprises function like California health care plans. Enrollees choose a doctor in Mexico whom they visit for routine care. In emergency or urgent care situations, they can use hospitals or clinics that are nearest to them, in California or Mexico.

Tijuana's rapid population growth has fueled a mini-boom in hospital construction, drawing some well-trained doctors from Mexico City and the United States, according to experts in both countries.

Part of what draws patients south of the border is the different medical culture. In California, some Hispanic patients say, medical care takes longer to get and is not delivered with a personal touch. These enrollees, who have received health care in both countries, say the U.S. system is too bureaucratic and hurries them out the door.

"Over there [in San Diego], we wait for more than half an hour and they just give us a Tylenol," said Guadalupe Briseno, a cross-border plan member who accompanied her 15-year-old son, Jorge, to the Tijuana clinic of Teresa Figueroa Garcia.

Garcia, 52, a soft-spoken family practitioner, is one of about 73 doctors in Tijuana who is part of Access Baja and shares her suite of offices with her husband, an internist.