Almost all contracts–oral or written–are enforceable if the party seeking enforcement can prove the existence of the contract and its terms. The party seeking to enforce the contact bears the burden of proof as to both the existence of the contract and its terms.
Contracts can be proven through the testimony of witnesses (including the parties), a stipulation as to the existence of the contract, or through the parties’ actions. Once the contract and its terms are established, the court has the power to enforce the contract, even if it is oral.
However, the Statute of Frauds requires that contracts concerning certain matters be in writing. These include contracts for the transfer of an interest in real property, as well as guarantees.
Although oral contacts are enforceable, courts are almost always more comfortable with enforcing a written contract.