Eight fire engines and a height vehicle arrived at the scene today (Friday) at 4.41pm.
After a thorough search, no fire was found.
The incident concluded for emergency services at 6.54pm.
Crews are continuing to investigate the cause of the smoke.
A spokesperson for Kent Fire and Rescue Service said: “Kent Fire and Rescue Service responded to reports of smoke in the day care centre at Darent Valley Hospital in Dartford.
“Eight fire engines and a height vehicle are in attendance, and following a search, no fire has been found.
“Crews are continuing to investigate the cause of the smoke.
“The day care centre has been evacuated.
“4.41pm on 2 August 2024.
“Stop time: 6.54pm.”