Unions representing six million workers planned to rally Wednesday in 35 cities from New York to Los Angeles to protest what they called inadequate health care coverage by Wal-Mart Stores Inc. (WMT), the nation's largest employer.

The Change to Win labor federation of seven unions, including two that have tried and failed for years to organize Wal-Mart workers, will denounce what it calls the "Wal-Mart health care crisis" in cities that also include Chicago, Atlanta, Boston and the Dallas suburb of Plano, Texas.

The rallies were organized together with WakeUpWalMart.com, a political campaign group started a year ago by the United Food and Commercial Workers union to pressure the retailer to raise pay and benefits and improve working conditions. The UFCW is part of Change to Win.

"Now is the time for Wal-Mart to seize the moment and become a better company. No hardworking American should ever have to live without health care or struggle to survive on poverty-level wages while corporate America makes obscene profits," said Paul Blank, campaign director for WakeUpWalMart.com.

The unions said in a statement that the Bentonville, Ark.-based company fails to provide company health care to 57 percent, or 775,000 employees, of its 1.34 million employees.

Wal-Mart has said 615,000 employees, or 46 percent, were enrolled in company health plans as of January versus 568,000 a year earlier.

The unions also cited an internal Wal-Mart memo, which became public last fall, that said 46 percent of the children of Wal-Mart workers were uninsured or on public health care.

Wal-Mart has defended its health care as better than average for the retail sector and twice since October has announced improvements, including shorter eligibility periods for part-time workers, coverage for their children and more affordable premiums between $11 and $23 a month.

The announcements reflect growing outside pressure on the company, which was exhibited in the state of Maryland recently. There, the state's legislature passed a law that requires companies with more than 10,000 Maryland employees to spend at least 8 percent of their payroll on employee health care or pay the difference into the state's Medicaid fund.

The Change to Win federation is made up of the carpenters' union, the laborers' union, the service employees, the Teamsters, United Farm Workers, UFCW and UNITE Here.