The emergency room at Lakeridge Health in Oshawa is overflowing.
Hospital officials say this is always a busy time of year but patient volumes have hit record levels.
At times, more than 60 people have been waiting for a bed.
The hospital has set up a command centre which includes a team that meets several times a day to monitor the situation in the ER.
There have also been long wait times at the ER in Bowmanville.
Hospital officials are reminding people to visit their family doctor or a walk-in clinic for non-emergencies.