If you hope to retire before 65, when Medicare eligibility begins, and won't get retiree health insurance from your employer, brace yourself.

"Health insurance is the biggest impediment to retirement for many people," warns Kathleen Muldoon, a certified financial planner. "They may be financially equipped to retire in every respect, but they have to continue working to keep their health benefits."

To stand a chance of making your early retirement dream come true, make sure that you can get affordable coverage before you quit working. Here are some options to consider:

• Continue employer-sponsored insurance. Coverage that you can get under the COBRA law can be a good bridge between your employer's group insurance and Medicare or an individual insurance policy. Under COBRA, companies that employ 20 people or more must let workers who have left or lost their jobs continue the same group insurance coverage for themselves and their families for up to 18 months. They'll have to pay the full premium, plus a 2 percent administrative fee.
  
  If you have group or COBRA coverage for at least 18 months (with no break in coverage of 63 days or more), you become eligible for HIPAA. It stands for the Health Insurance Portability and Accountability Act, which Congress passed in 1996.) It gives you the right to buy individual health insurance that doesn't exclude or limit coverage for pre-existing medical conditions.
  
  
• Buy an individual policy. Check out your options in the state where you currently live, or where you plan to move to after you retire. Start your research on www.healthinsuranceinfo.net, a Web site maintained by Georgetown University's Health Policy Institute. Also visit the Web site for your state's department of insurance. (To find it, go to the National Association of Insurance Commissioners' site, and click on "NAIC States and Jurisdictions.")
  
  You can search for premium quotes at www.ehealthinsurance.com , but be aware that you'll probably pay more if you're not in perfect health. Finally, an independent insurance agent may be able to help you find an appropriate policy. To find one, go to the National Association of Health Underwriters' Web site.
  
  
• Look into high-risk pools. If you're uninsurable in the open market, you might be able to obtain coverage through a high-risk pool, which exists in 35 states. Premiums are generally capped at 1.25 to 2 times the cost of private insurance. All state high-risk pools adjust premiums for age, which makes coverage very expensive for retirees in their 50s or early 60s. The rate you'll pay sometimes depends on where you live within a state.
  
  Consider, for example, a nonsmoking man age 63 who buys coverage from the Texas Health Insurance Risk Pool. Depending on his Zip code and whether he chooses a $1,000, $2,500, $5,000, or $7,500 deductible, he'll pay $464 to $1,380 a month for coverage. For more information on state high-risk pools, go to www.healthinsurance.org/risk_pools/.