Professional liability insurance—sometimes called malpractice insurance or errors and omissions insurance—is insurance that may be purchased by attorneys and law firms to pay the costs of defending legal malpractice claims, and the costs of settling such claims or paying the judgment awarded to a plaintiff on such a claim. Most states do not require attorneys to purchase professional liability insurance, but some states require attorneys who do not carry professional liability insurance to provide notice to their clients of that fact. Some states require attorneys to have their clients sign a written disclosure that the attorney does not have professional liability insurance.

In Maine, attorneys are not mandated by state law to carry professional liability insurance, also known as malpractice insurance or errors and omissions insurance. However, the Maine Rules of Professional Conduct require attorneys who do not have professional liability insurance to inform their clients of this lack of coverage. Specifically, Rule 1.4(c) of the Maine Rules of Professional Conduct states that a lawyer who knows that the lawyer does not have professional liability insurance shall inform a new client in writing at the time of the client's engagement of the lawyer that the lawyer does not have professional liability insurance of at least $100,000 per occurrence and $300,000 in the aggregate per year. This disclosure must be made to the client in writing and must be acknowledged by the client. This requirement ensures that clients are aware of the risks involved in hiring an attorney without malpractice insurance and can make informed decisions about their legal representation.