Gay rights advocates hailed the move as a major step toward fairness for lesbian, gay, bisexual and transgender Americans.
"This is a critical step in ending discrimination against LGBT families and ensuring that, in the event of a hospital stay, all Americans have the right to see their loved ones," said House Speaker Nancy Pelosi, D-Calif.
With no fanfare, the White House on Thursday night released a statement by Obama instructing the Health and Human Services Department to draft rules requiring federally subsidized hospitals to grant all patients the right to designate people who can visit and consult with them at crucial moments.
The designated visitors should have the same rights that immediate family members now enjoy, Obama's instructions said. It said Medicare-Medicaid hospitals, which include most of the nation's facilities, may not deny visitation and consultation privileges on the basis of race, color, national origin, religion, sex, sexual orientation, gender identity or disability.
The new rules, Obama said, should "guarantee that all patients' advance directives, such as durable powers of attorney and health care proxies, are respected," and that patients' designees be able to "make informed decisions regarding patients' care."
Some gay advocacy groups say Obama has moved too slowly to fulfill campaign promises to expand their civil rights. The nation's top military leaders recently said it is time to end the "don't ask, don't tell" policy that has kept gays from serving openly in the armed services.
The Human Rights Campaign, which backs gay rights, said Obama's hospital decision was inspired in part by a New York Times article about a lesbian couple in Miami. They were kept apart while one lay dying in a hospital despite having an "advanced health care directive" asking for full visitation rights for each other.
"Discrimination touches every facet of the lives of lesbian, gay, bisexual and transgender people, including at times of crisis and illness," said HRC President Joe Solmonese. "The president's action today will help ensure that the indignities" suffered by the Miami patient and her children will not happen to others.
In his statement, Obama said: "Every day, all across America, patients are denied the kindnesses and caring of a loved one at their sides -- whether in a sudden medical emergency or a prolonged hospital stay. Often, a widow or widower with no children is denied the support and comfort of a good friend."
He added: "Also uniquely affected are gay and lesbian Americans who are often barred from the bedsides of the partners with whom they may have spent decades of their lives -- unable to be there for the person they love, and unable to act as a legal surrogate if their partner is incapacitated."
Without the expanded visitor-designation rights, Obama said, "all too often, people are made to suffer or even to pass away alone, denied the comfort of companionship in their final moments while a loved one is left worrying and pacing down the hall."