**Yes, generally—assuming this was an ordinary personal cheque.** Delivering that cheque normally makes payment conditional on the bank honouring it. Since it was never cashed and you stopped payment, the rent obligation remains. Quebec’s [Civil Code, article 1564](https://www.legisquebec.gouv.qc.ca/fr/version/lc/CCQ-1991?code=se%3A1564&history=20170331), expressly recognizes a **certified cheque** as a means of discharging a debt; an ordinary personal cheque does not provide the same guarantee.

There is also a provision specifically addressing lost instruments: [section 155 of the federal Bills of Exchange Act](https://laws-lois.justice.gc.ca/eng/acts/B-4/section-155.html) allows a holder to demand a replacement for a bill lost before it is overdue, with security against liability if the original resurfaces. [Section 165(2)](https://laws-lois.justice.gc.ca/eng/acts/B-4/section-165.html) makes the relevant bill provisions applicable to cheques.

On the facts you describe, replacing the cheque completes payment of that month’s rent. Your lack of fault for the theft does not, by itself, extinguish the debt.

When you provide the replacement, get written confirmation identifying the rent month and the cancelled cheque it replaces. You can also ask the landlord to reimburse any stop-payment fee; entitlement to those incidental costs is a separate question from whether the rent remains payable.