Mother arrives at childcare to learn her daughter had been taken home by someone else.

A Florida woman lived every parent’s worst nightmare when she arrived at her child’s daycare to discover one of her daughters had been taken home by someone else.

It was a normal Friday afternoon for 32-year-old Holly Smith, who went to pick up her two daughters from Pathways Early Learning Center.

When she got there, she discovered one of them had been picked up by a stranger.

“I went to find my 4-year-old and she was gone,” Smith told News 6.

Daycare employees told her that someone who said they were a co-worker told them Holly had sent them to pick up her daughter.

Workers told Smith they had phoned her to verify it was OK.

"Well, they didn’t talk to me," Smith responded.

In a panicked call to 911, Smith told authorities "somebody has taken my daughter".

"They said someone gave them an I.D. and that I'd approved them to pick her up but I didn't!"

Smith described the hours her daughter was missing as "two hours of pure hell".

It wasn't until the daycare centre was close to closing that staff had realised what had happened.

"There was another child left behind, that we figured [it] out, this other adult took the wrong child," she said.

Smith's daughter was brought back to the centre, and the right child was taken home.

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"I was relieved to see her," Smith said of being reunited with her young daughter.

Smith said the mistake by the day care centre - which she specifically picked for its security features and the fact they required photo identification from every adult picking up a child - was "inexcusable".

"They have all of these security measures, and it was still allowed for my child to go home with the wrong person," she said.

She has since removed her children from the centre.