Beginning on January 1, 2006, Medicare began providing prescription drug coverage to all registered Medicare recipients. This coverage is known as Medicare Part D. The actual prescription drug coverage insurance is provided by private, Medicare-approved companies. You will need to choose a company from among those approved to provide this Medicare benefit based on what each plan covers, as well as how much the monthly premium will be. All plans provide coverage that at least matches the standard Medicare prescription drug plan. Plans with higher monthly premiums are likely, though not guaranteed, to provide more coverage of a wider range of drugs. If you already have prescription drug coverage through a current or former employer, if you are retired, keep in mind that your existing benefit may actually be better than those provided as a Medicare-approved plan. If you choose not to enroll in the Medicare drug plan when you are first eligible, you may be charged a penalty for joining later.