Proving Legal Malpractice in New York State: An (Almost) Comprehensive Guide



Legal malpractice occurs when an attorney breaches their duty of care, resulting in harm to their client’s interests. Proving legal malpractice in New York State requires establishing four essential elements, each of which must be meticulously supported by evidence and legal expertise. This article will outline the steps and considerations necessary to navigate the complex process of proving legal malpractice in the Empire State.

  1. Establishing the Attorney-Client Relationship

The first crucial step in proving legal malpractice is to demonstrate the existence of an attorney-client relationship. This relationship serves as the foundation of any legal malpractice claim. A written contract, formal agreement or an “engagement letter” from/with the attorney may establish the relationship, but it can also be implied through the attorney’s actions. Even when an attorney offers “free advice” with nothing in writing a court may determine that an attorney/client relationship was established.

2. Demonstrating the Breach of Duty

To succeed in a legal malpractice claim, the plaintiff must prove that the attorney breached their duty of care. In New York State, attorneys are expected to act with the skill and competence that other reasonably prudent attorneys would exhibit under similar circumstances. The standard of care is measured by the accepted norms and practices within the legal community.

Expert testimony from another qualified attorney is usually  necessary to demonstrate how the defendant’s actions deviated from the standard of care. This expert should outline what the attorney should have done in the same situation, highlighting the mistakes made and demonstrating how these errors negatively impacted the client’s case.  It is usually impossible to prove legal malpractice without the testimony of an “expert” lawyer regarding how the defendant/attorney’s actions fell below the acceptable standard of care. An exception is where there is “per se” negligence, for example allowing a statute of limitations to expire.

3. Establishing Causation and Damages

Proving that the attorney breached their duty is not enough; the plaintiff must also demonstrate that the attorney’s negligence  caused harm or damages to their client. It is vital to establish a link between the attorney’s actions and the negative outcome experienced by the client. In New York, unlike in other states, the client need not prove that her damages would not have ensued “but for” the attorney’s malpractice.  It is enough to prove that the malpractice was a “substantial factor” in causing the harm.

Quantifying the damages resulting from the attorney’s malpractice is a critical aspect of the case. Financial records, and expert testimony, may be used to support the plaintiff’s claims of damages.

If the malpractice caused the client to “lose” a case the attorney was handling, or to have settled that prior case for less, then the client must “prove the case within the case”.  This means the client must prove that the attorney’s mishandling of the underlying case caused that case to be lost or to lose its value so that the settlement was lower than it otherwise should have been. Otherwise stated, the client must prove that the underlying case would likely have been won had the attorney not malpracticed it. This requires putting in proof of the underlying case and having a jury decided that the client would have prevailed in the underlying case.

In any malpractice claim in New York, the client can also claim back all the attorney’s fees paid to the lawyer and interest at 9% annual rate on the judgment from the time of the malpractice.

4. Timely Filing of the Lawsuit

In New York State, legal malpractice claims are subject to a three-year statutes of limitations. Although the three-year clock generally starts ticking from the date the malpractice occurred (regardless of when the client discovered the malpractice), there are many exceptions.  One exception is where the attorney continued to represent the client on the same matter after the legal malpractice occurred.  In that case, the statute of limitations may be “tolled” (not start to run) until the lawyer finishes representing the client on that same matter.  Calculating a statute of limitations is complicated and should be done only by an experienced attorney.  Missing the statute of limitations is the death knell to a malpractice case, so great care must be taken in this regard.


Proving legal malpractice in New York State is a complex and challenging endeavor. Plaintiffs must navigate intricate legal principles, present a compelling case supported by evidence, and adhere to strict deadlines. To maximize the chances of success, it is crucial for clients to seek experienced legal counsel to handle their legal malpractice claim.

Mike Bersani

(Repeatedly named “Attorney of the Year” by fellow lawyers and judges for representing plaintiffs in legal malpractice claims in the Syracuse New York metropolitan area)

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Michaels Bersani Kalabanka P.C.
Syracuse NY Legal Malpractice Lawyers
Michaels & Smolak, P.C.

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