Can a cohabitation agreement release a common-law partner's right to claim dependant support from the estate?

It can, and a properly executed cohabitation agreement releasing estate claims is generally more likely to be enforced than an informal or undocumented understanding between partners. Ontario family law gives specific legal effect to properly signed domestic contracts, and a cohabitation agreement is one of the recognized types — so a clear release clause covering claims against each other's estates carries real legal weight.

That doesn't mean a release is bulletproof in every case. A court can still scrutinize how the agreement was made — whether both partners understood what they were signing, whether there was proper financial disclosure, and whether the agreement was otherwise validly executed. A surviving partner might also argue circumstances changed enough after signing that the release shouldn't be read to cover a later dependant support claim, though that's a harder argument to win against clear release language. Because so much turns on the specific wording of the release and how the agreement was put together, anyone relying on — or trying to get around — a cohabitation agreement's estate release should have both the agreement and their situation reviewed by a lawyer rather than assuming the clause simply settles the matter either way.