"What we want to assure seniors around the country is that there is help. You can call 1-800-MEDICARE. You can get on the Internet with Medicare.gov," Mr. Bush said Tuesday.
On a visit to Greenspring Village Retirement Community outside Washington, Mr. Bush noted the drug plan is optional but called it "a good deal" for seniors.
Some seniors have found the enrollment process confusing, and signup has been slow for the low-income subsidy.
"For some seniors, this is a daunting task," Mr. Bush said. "When you give people choice and options ... it can be a situation where people say, 'I don't really — this is something I may not want to do.'"
The Department of Health and Human Services expects about 28 to 30 million beneficiaries to sign up during the enrollment period, which continues through May 15.
Frank Sinatra was crooning over a sound system as Mr. Bush visited with residents and experts who were there to answer questions about the program. Greenspring, home to more than 2,000 moderate-income residents, is managed by Erickson Retirement Communities based in Catonsville, Md.
John Erickson, chairman of the company, said the prescription drug benefit presents a tough decision for some retirees.
"I'd say about 40 percent are depending upon their children for some additional assistance in helping understanding the program," he said.
In most states, beneficiaries will be able to select from at least 40 plans. Some plans offer prescription drug coverage only. Others offer managed care that covers the full range of Medicare services, such as visits to a doctor's office. While some find the vast number of plans confusing, federal officials say the competition forces insurers to lower costs and provide more generous benefits for people 65 and older and the disabled.
Sen. Edward Kennedy, D-Mass., said one woman told him that she called Medicare three times with questions about enrollment and received three different answers. Seniors with drug coverage through Health Maintenance Organizations and retiree plans are being told to sign up for the new prescription drug plans, only to find out that by doing so, they lose their existing coverage, he said.
"Seniors are given information that contradicts itself and volunteers who are supposed to help navigate the maze of plans and options are overworked to the point of exhaustion," Kennedy said.