Short answer. Generally yes — a novation built on a void original obligation is itself void. Article 1298 of the Civil Code states that the novation is void if the original obligation was void. Two narrow exceptions apply: when only the debtor may raise the nullity, or when ratification cures a voidable defect.
What the law says
The novation is void if the original obligation was void, except when annulment may be claimed only by the debtor or when ratification validates acts which are voidable.
Civil Code, Article 1298 — Void Original Obligation. Read the full provision →
The general rule: a void source produces a void novation
Novation is the act of replacing one obligation with a new one, either by changing the parties, the object, or the principal conditions. Article 1298 lays down a foundational limit: if the obligation being replaced was void from the start, the novation shares that defect. A void obligation has no legal existence, so there is nothing to novate. The new agreement, though it may appear valid on its face, inherits the nullity of its foundation. You cannot cure a void obligation simply by replacing it with a new one.
First exception: when only the debtor can raise nullity
The article carves out one important exception. If the original obligation is voidable — meaning it is valid until annulled — and only the debtor has standing to seek annulment, then a novation made before the debtor exercises that right can be valid. This happens, for instance, when the original obligation was entered into by the debtor through vitiated consent. The defect belongs to the debtor to invoke or waive. If the debtor agrees to a novation instead of claiming annulment, the new obligation stands.
Second exception: ratification of a voidable obligation
The statute also recognises that ratification validates acts which are voidable. If the original obligation was voidable — not absolutely void — the party entitled to seek annulment may instead ratify it. Ratification confirms the defective act and cleanses it of the vice. Once a voidable obligation has been ratified, it becomes fully valid and a novation based on it is likewise valid. The key distinction is between void obligations (which cannot be ratified, cured, or novated) and voidable ones (which can be cured by the party they protect).
Practical question: was your original debt truly void?
The difference between void and voidable matters enormously here. A void obligation is one that the law treats as never having existed — it cannot be ratified, enforced, or novated. A voidable obligation, by contrast, exists and binds the parties until successfully annulled. Common examples of void obligations include those with an illegal cause or object, or those involving simulated transactions. Voidable obligations include those tainted by mistake, fraud, intimidation, or undue influence. If your original debt was merely voidable rather than absolutely void, there may be a path to sustaining the new agreement.