A Letter of Intent to Sue, commonly called a demand letter, is a formal pre-litigation notice that informs a party of your intent to file a lawsuit unless the dispute is resolved within a specified timeframe. Under Federal Rule of Civil Procedure 11, attorneys must conduct reasonable inquiry before filing suit, and a demand letter satisfies this requirement by demonstrating good-faith resolution efforts. Many state statutes and court rules require or strongly encourage pre-suit notice before commencing litigation.

The demand letter serves multiple strategic purposes beyond simple notification. It preserves the sender's legal position, tolls statutes of limitation in certain jurisdictions, and creates a documented record of the claimant's attempt to resolve the matter without judicial intervention. Under Evidence Rule 408 (Federal Rules of Evidence), settlement communications during negotiation are generally inadmissible, but the demand letter itself establishes the existence and nature of the dispute.

Courts in many jurisdictions view pre-suit demand letters favorably when assessing attorney fee awards under fee-shifting statutes. For example, under 42 U.S.C. Section 1988 (civil rights claims) or the Fair Debt Collection Practices Act (15 U.S.C. Section 1692g), a properly crafted demand letter can strengthen fee recovery motions by demonstrating the defendant's opportunity to resolve the claim before litigation costs accrued. The letter also satisfies pre-suit notice requirements under specific statutes such as the Consumer Product Safety Act and state tort claims acts governing suits against government entities.

Pre-suit demand letters are warranted across a broad range of civil disputes. A contractor who completed a $45,000 kitchen renovation but received only $20,000 sends a demand letter specifying the breach of contract and the remaining balance due within 30 days. A landlord whose commercial tenant caused $12,000 in property damage beyond normal wear and tear issues a demand before filing in small claims or district court.

Tort claims present another common use case. A personal injury claimant sends a demand letter to an at-fault driver's insurance company detailing medical expenses, lost wages, and pain and suffering before filing suit. Under state tort claims acts (such as California Government Code Section 910 or Florida Statute Section 768.28), claims against government entities require formal pre-suit notice within strict deadlines, typically 6 months to 2 years.

Business disputes frequently begin with demand letters: a former employer pursuing enforcement of a non-compete clause, a franchisor demanding cure of franchise agreement violations, or a creditor seeking payment on a defaulted promissory note. Intellectual property disputes, including trademark infringement under the Lanham Act (15 U.S.C. Section 1125) or copyright infringement under 17 U.S.C. Section 501, almost always begin with cease-and-desist demand letters before litigation commences.

An effective demand letter requires several precise components. The sender and recipient must be identified with full legal names and addresses. The factual basis of the claim must be stated with specificity, including dates, locations, and events giving rise to the dispute. Vague allegations undermine credibility and reduce the letter's persuasive force.

The legal basis section should cite the specific cause of action: breach of contract (Restatement (Second) of Contracts Section 235), negligence, statutory violation, or other applicable theory. Include the specific damages sought with a breakdown showing how the amount was calculated, such as principal owed, interest accrued, consequential damages, or statutory penalties.

A firm deadline for response is essential, typically 10 to 30 days. The letter must state the consequences of non-compliance, specifically that a lawsuit will be filed in the appropriate court if the demand is not met. Identify the court and jurisdiction where suit would be filed to demonstrate seriousness and legal preparedness.

Include a statement that the letter constitutes a good-faith attempt to resolve the dispute without litigation. Reference any contractual dispute resolution prerequisites such as mandatory mediation or arbitration clauses. If the underlying agreement contains an attorney fees provision, note that the prevailing party will seek recovery of litigation costs and fees. The letter should be sent via certified mail with return receipt requested to create proof of delivery, which is critical for establishing actual notice under due process requirements.