Advocates say more are looking than finding.
The Census report, released in September, shows more than 280,000 Oklahoma parents have children age 6 or younger.
Of those, nearly 172,000 parents told the Census Bureau that every adult in the house was in the workforce, meaning they are working or looking for work.
There aren't enough quality child-care providers to meet that kind of demand, advocates say.
Karen Smith, director of Child Care Resource Center, said the shortage is especially true for infants and toddlers.
Parents who work beyond the 8 a.m. to 5 p.m. work day also face difficulty in finding quality child care because they aren't able to pick up their children, Smith said.
Parents of infants and younger children face real problems getting care, said David Blatt, director of public policy for the anti-poverty agency Community Action Project of Tulsa County.
Fewer slots are available and it's more expensive to care for them, Blatt said.
George Johnson, communications director for Department of Human Services, said that overall there is quality child care in Oklahoma and children are being taken care of.
DHS has been under fire because of its handling of high-profile child abuse cases, including the death of Joshua Minton, 2, who died in May. Vicki Leigh Chiles, who operated a home-based child care, is charged in Minton's death.
Each child-care facility in Oklahoma receives three random visits every year, Johnson said.
"That doesn't include visits because of complaints," he said.
Roughly 80 percent of children age 5 and younger are in some type of child care, Smith said.