WASHINGTON (AP) _ The number of people donating kidneys and, increasingly, sections of their livers, while still alive has more than doubled over the past decade, as transplant patients facing years on a waiting list look for other options.

Much of the increase comes from donations by donors who are not related to the transplant patient _ usually a close friend, according to a report released Tuesday by the United Network for Organ Sharing, which runs the nation's transplant system. These donations more than tripled between 1989 and 1998.

``It's just something anyone in my group would do,'' said Kyle McNamara, 32, of Braintree, Mass., who donated part of his liver to a co-worker in January. ``After talking to the surgeons and really getting the information, it really wasn't a hard decision.''

Nationwide, there were 4,273 living donors in 1998 _ up from 1,918 a decade earlier, the organ-sharing network said. In 1998, one in five donated organs came from a living donor.

Of the living donors, nearly 18 percent were from people who were not related to the patient. About 40 percent were siblings, 20 percent parents, 16 percent offspring and 7 percent other relatives. Just a few donors are complete strangers.

``At first I said no,'' said Maureen Kennedy, 62, of Niverville, N.Y., who had only six months to live when her son Andrew gave her a piece of his liver. ``He said, `Ma, you can't do that to me.' He said, `You gave me life and now it's my turn to repay it.'''

Four months after the surgery, both Kennedys are doing well.

Donations from people who have died _ called cadaveric donors _ have also increased, though not as dramatically, and only because there's been an increase in the number of older donors. Donors over age 50 now account for 29 percent of all cadaveric donors.

All together, there were 5,798 cadaveric donors in 1998, up about 6 percent from 1997 and about 45 percent since 1989.

Still, in 1998, 4,860 people died waiting for a transplant, triple what it was a decade earlier. The number of people on the waiting list also tripled, to 64,373 by the end of 1998.

Today, the waiting list tops 68,000.

Those bleak numbers make people more interested in helping out, experts say.

``Family members are more inclined to ask (about donating), seeing their loved one progressing before their eyes and knowing they're still a long way from being at the top of the list,'' said Dr. Elizabeth Pomfret, director of the live donor liver transplant program at Lahey Clinic in Burlington, Mass.

Living kidney donors have been around for a long time _ the first transplant ever performed was a kidney moved from one twin brother to another in 1954. People are born with two kidneys but only need one to function.

Living liver donors are newer, particularly between adults. For years, doctors have transplanted a small piece of an adult liver into a child. Now, increasingly, they are transplanting larger sections into other adults. As the technique has improved, the numbers have grown.

And data are accumulating that kidneys from living donors do better in their new bodies than kidneys from cadaveric donors, partly because it is outside the body for a shorter time before transplantation.

With those results, doctors are more willing to consider donors who are not related to the recipient, though every donor must go through a full psychological evaluation to be sure they have not been coerced in any way and that they are not being paid.

The shortage of organs _ combined with medical experience _ also account for the increase in older, deceased donors. Conventional wisdom once held that donors over 55 or 60 did not have usable organs. That's no longer true, especially for livers and kidneys, said Howard Nathan, director of the Gift of Life Donor Program in Philadelphia, where they regularly procure organs from older donors.

``Ten years ago, some donors would not have been considered for transplantation just on a gut reaction,'' he said. ``We now find donors as old as 80 can be used safety.''