Short answer. Yes, to be enforceable by suit. A lease of real property for longer than one year falls under the Statute of Frauds, so a purely verbal three-year lease is unenforceable by court action unless there is a written note or memorandum signed by the party charged — or unless the agreement has been ratified.
What the law says
An agreement for the leasing for a longer period than one year, or for the sale of real property or of an interest therein
Civil Code, Article 1403 — Unenforceable Contracts and the Statute of Frauds. Read the full provision →
Leases over a year need writing
Article 1403's Statute of Frauds expressly covers an agreement for the leasing for a longer period than one year, or for the sale of real property or of an interest therein. A three-year lease is a leasing for longer than one year, so it lands squarely inside the statute. That means your oral lease is unenforceable by action: without a written note or memorandum subscribed by the party you seek to hold, a court will not compel performance of the three-year term over that party's objection. The oral agreement is not void, but it lacks the written proof the statute requires.
One year is the dividing line
The statute draws its line at duration. A lease of real property for one year or less is not caught by this clause and can be enforceable though purely verbal. It is the excess beyond one year that triggers the writing requirement. So the length you agreed to matters: three years is well past the threshold. Because the clause pairs leases over a year with sales of real property or interests in it, the law treats a long lease as a substantial dealing with land that deserves the same protection against uncertain, purely spoken proof.
What the writing must show
A full formal contract is not required — a note or memorandum suffices — but it must record the essential terms of the lease and be subscribed by the party charged, or by his agent. Signature by the person you want to hold liable is what makes the writing effective against him. Where no such writing exists, the statute bars even oral evidence of the lease offered to enforce it. This is why long leases are ordinarily put in a signed writing at the outset: it is the only reliable way to make the agreed term enforceable in court.
How an oral lease can still bind
Unenforceability is a defense that can be lost. Article 1403 makes these contracts enforceable if ratified. Where the lessor accepts rent and lets the lessee take possession under the agreed term, or a party fails to object to evidence of the lease in court, the arrangement may be taken out of the statute. Partial performance the other side accepts can have the same effect. So a verbal long lease that both sides have begun to honor is not necessarily unenforceable; the statute mainly protects a party who timely objects to being held to an unwritten term.