What the ON00880 is for
Long-term illness leave came into force on June 19, 2025. It lets an employee covered by the ESA, employed for at least 13 consecutive weeks, take up to 27 weeks of unpaid leave in a 52-week period when a serious medical condition keeps them from work. The weeks don’t have to be consecutive. The certificate is what the employer can ask for as proof. It doesn’t pay the employee anything, which patients often expect. Income comes from EI sickness benefits or a disability plan, each with its own forms.
Who completes it
The health practitioner completes the whole form. A physician, registered nurse or psychologist can issue it, and Ontario’s guide includes nurse practitioners and psychiatrists. The employee has no section. They give the employer a copy as soon as possible after the employer asks.
How to fill in the certificate
Patient’s information and examination date
Enter the patient’s name and the date you examined them. The certificate speaks to the conditions that existed on that date.
A. Serious medical condition
Answer yes or no. The form notes that a serious condition can be chronic or episodic. The certificate doesn’t need the diagnosis, so leave it off.
B. Period off work
Give the from and to dates the patient won’t perform work because of the condition. If they stopped working before you saw them, use the earlier date, as the form instructs. A shorter period than the patient needs limits the leave to that period, so estimate the full expected absence.
Information of health practitioner
Give your name, address, phone, fax and email, tick physician, registered nurse or psychologist, and add your licence number, signature and date.
Common reasons it’s questioned
- A period with no end date.
- A start date later than the day the patient actually stopped working.
- A diagnosis written in, which the employer doesn’t need.
- A period longer than 27 weeks, which the leave can’t exceed in a 52-week window.
- No licence number or practitioner type ticked.
Submitting it
The patient gives the certificate to their employer. Nothing goes to the ministry.