It's no longer just a place to visit on weekends and holidays — for more American children, Grandma and Grandpa's house is home.

The number of kids under age 18 living in a grandparent-headed home increased in nearly every state for which the latest round of 2000 census data is available. Figures released Wednesday for Florida, for instance, showed 258,952 kids living in such homes, a 33 percent rise since 1990.

The trend is reminiscent of the pre-World War II years, when three-generation households were not uncommon, said Gregory Brock, director of the University of Kentucky Family Center.

But the findings also come at a point when the issue of visitation and custody rights for grandparents has become a sensitive one in courts and legislatures across the country.

And for grandparents raising kids without one of the grandchild's parents living with them, it has become an unexpected financial burden that lawmakers must ease with more financial assistance, said Amy Goyer, a program coordinator for AARP, the country's largest advocacy group for senior citizens.

Jim and Toni Landenberger, of Naples, Fla., were awarded custody of their two grandsons after their daughter — the boys' mother — was sent to prison and the boys' father died. A lengthy custody fight with the father's family drained their savings.

The Landenbergers say they are happy and that the fight for their grandsons was worth it. But money concerns weigh on their mind.

"It's nothing you really planned for, because there is no such thing as retirement now," Mrs. Landenberger said. "You are doing things around school that you hadn't planned on doing."

The figures offer another perspective into the more diverse makeup of the American family highlighted by the 2000 census.

In Florida, for instance, the percentage of children under 18 living in a grandparent-headed home rose from 6.8 percent in 1990 to 7.1 percent in 2000.

Children living in married-parent homes still represented the majority in Florida — 2.2 million, or 61.3 percent of all kids there in 2000. But that share was down from 65.8 percent a decade ago.

Data also released Wednesday for Hawaii showed that 12.9 percent of children there lived in a grandparent's home in 2000, up from 10.4 percent in 1990.

Meanwhile, 61.9 percent of Hawaiian kids lived in married-parent homes in 2000, down from 69.4 percent in 1990.

"Society in general is beginning to understand more about grandparents raising grandchildren," said Kathy Reynolds, of Enfield, Conn. After her daughter went into drug rehab, Reynolds gained custody of her 5-year-old granddaughter.

A 1997 Census Bureau survey estimated that more than half the kids living in grandparent-headed homes had their mother living in the house with them. About one-third of the homes did not include one of the grandchild's parents.

National numbers from the 2000 census will not be available until after all 50 states get their data, expected by mid-August.

Additionally, these figures do not show, for instance, the number of grandparents living in a home headed by their own son or daughter and play a caregiving role for grandchildren. That kind of information is expected to be released next year.

The 1990 census found 3.5 million children under age 18 in the United States, or 5.5 percent of kids, living in a grandparent-headed home, up from 3.2 percent of kids in 1970.

While previous studies have shown that grandparent-headed households occur more in low-income families, divorce, career choices and job constraints are causing the numbers to rise in all socio-economic groups, Brock said.

An increase in drug abuse in recent decades has also contributed to the trend as addicted parents suffer health problems, enter rehabilitation programs, or are jailed, he said.