The YM-YWHA daycares in Pierrefonds and Snowdon were closed to about 160 children, because of a stalemate in contract talks between educators and management.
A government-appointed conciliator couldn't bridge the gap, said daycare spokesman Jonathan Goldbloom.
"We didn't take this step lightly, but we felt we had put a reasonable offer, and it was turned down," he said.
The 20 or so educators at the centres want to be paid for days when the daycare is closed, such as during Jewish high holidays.
Ruth Dahan, who has worked at the Pierrefonds daycare for 24 years, said the lockout was difficult.
"The parents were crying and I was crying because I have so many sentiments," she said, as she stood outside the building.
Dahan's co-worker Jennifer Smolar said the situation is upsetting to educators and parents.
"I don't understand how they can do this... aside from doing it to us, you're taking away spaces from parents."