The Year Law Firms Stopped Debating AI and Started Using It

Law firm leaders appear to have made a clear decision about artificial intelligence over the last year: Resistance is futile.

The third annual Best Law Firms U.S. Legal Market Report, a survey of nearly 5,800 U.S. firms, shows a sharp spike in AI implementation and a corresponding nosedive in the number of firms refusing to entertain the use of generative AI (GenAI) tools. The data was collected during Best Law Firms' annual research and rankings process and includes firms from all 50 states and the District of Columbia, from solo practitioners to global megafirms.

The results confirm the rapid adoption of AI by law firms and the depth of its impact on their operations, especially at midsize and large firms.

Law Firm AI Adoption in 2026: From Discussion to Implementation

Sixty-four percent of law firms with 20 or more lawyers said they had fully implemented GenAI tools across multiple practices or were piloting AI tools in select practice areas, a leap of 25 percentage points from Best Law Firms' 2025 survey.

Firms are also moving from the discussion phase to actually using tools. The percentage of those firms merely exploring the potential for GenAI adoption fell from 50% to 31%.

Fewer Firms Are Opting Out of Generative AI

The number of firms that said they have no plans to adopt generative AI plunged by more than half, from 11% to 5%. Firms in the 20-49-lawyer size range saw the biggest decline in resistance, from 14% in 2025 to 7% in 2026.

Large Firms Lead on Full AI Implementation

The largest firms in the survey, those with 150+ lawyers, have moved fastest and farthest. In 2026, 56% of large firms have fully integrated AI tools into multiple practice workflows, up from 23% the previous year. Overall, full implementation among firms with 20+ lawyers more than doubled, increasing to 28% from 11%.

Midsize and Smaller Firms Embrace AI Pilot Programs

Pilot programs flourished among smaller and midsize firms. Thirty-six percent of firms in the 20-49-lawyer and 50-149-lawyer categories said they are experimenting with tools in select practice areas, up roughly 10 percentage points in both size tiers. One-third of large firms said they are piloting tools.

Like their larger peers, most midsize law firms (50-149 lawyers) have moved on from the discussion phase to AI usage. All told, 70% have either fully implemented or are piloting GenAI tools, a 30-point increase from 2025. The next size tier (20-49 lawyers) saw a similar jump in AI usage, though a higher percentage (39%) are still discussing the potential for generative AI adoption.

How Law Firms Talk to Clients About AI

One of the most telling signs that firms are embracing AI is their increasing willingness to talk about the technology with their clients. In 2025, many of the firms using or experimenting with AI were reticent to admit it. Some 43% of those firms said they did not disclose AI use to clients. This year, that number has been halved.

Solo practitioners and smaller firms with 2-19 lawyers are the least likely to disclose AI usage. However, just 1% of firms with 150+ lawyers and 3% of firms with 50-149 lawyers do not provide information about AI usage to clients.

AI Becomes a Selling Point

This year's survey shows big gains among firms making AI use a selling point with current and prospective clients. Overall, 17% of firms said they discuss their AI acumen as part of their value proposition, more than triple 2025's number. Firms with 20+ lawyers are the most likely to make AI a selling point:

• 150+ lawyers: 43% discussed AI as part of their value proposition in 2026, up from 23% in 2025.
• 50-149 lawyers: 13% made AI a selling point in 2025. That number climbed to 31% in 2026, a 138% jump.
• 20-49 lawyers: In the 2025 survey, no firms in this tier were touting AI to clients. Now, 20% are doing so.

The most popular strategy is to reveal AI usage when clients inquire. Overall, 23% of firms said they preferred this method, a figure that includes firms that do not currently use AI. Among firms that have implemented or are piloting AI tools, the percentage climbs to 45%.

How Law Firms Are Using AI: Six Top Use Cases

As firms grow more comfortable with artificial intelligence, the use cases have grown. The survey asked firms with 20 or more lawyers about six areas of AI usage. Each area saw growth of 200% or more over last year.

1. Legal research. The most popular AI option, identified by 75% of firms as an area where they were using or planning to use AI, up from 23% in 2025.
2. Marketing content and pitches. Last year, 20% of firms said they intended to use AI to assist with marketing content. This year, the number climbed to 66%, including nine out of 10 firms with 150+ lawyers.
3. Drafting contracts and other legal documents. Just over half, 52%, of firms are deploying AI for drafting work, a massive increase from 14% last year.
4. Routine correspondence. AI is helping lawyers write client updates, summaries and emails and handle other routine tasks at 50% of the firms surveyed, up from 15% in 2025.
5. Knowledge management systems. Forty-nine percent of firms are using AI for knowledge management, up from 14%.
6. Litigation risk and strategy analysis. While still the least used option, more than one-third of firms are using or planning to use AI to game out disputes. Last year's figure was 9%.

AI Risk Factors: Training, Policies and Hallucinations

Even as AI tools become an everyday part of the workflow, firms also appear to be taking greater precautions to reduce AI-related risks:

• Training: Nearly two-thirds of firms now train their lawyers on the limitations and risks of generative AI. Last year, just one-fifth did.
• Policies: Nearly half of firms now have clear policies on when GenAI can be used in client matters, up from 14% last year.
• Auditing: One-third regularly audit AI outputs for accuracy, triple the 2025 share.
• Client consent: 28% ensure they have client consent to use AI on their matters, up from 20% in the previous survey.

Big firms have ramped up the most. Only 4% of firms with 150+ lawyers were conducting training in last year's survey. In 2026, nearly 90% are. While 19% of large law firms had implemented clear AI use policies in 2025, 95% say they have them today.

The Legal and Ethical Stakes of AI Hallucinations

Firms of all sizes have good reason to be wary about AI’s ethical and legal risks. During the first nine months of 2026 alone, lawyers in more than 330 U.S. cases have filed documents with AI errors that have been caught by the courts. Some 70 of those cases have resulted in monetary fines and sanctions, with several others still pending. The figures come from a global database tracking legal decisions in cases where artificial intelligence has produced hallucinated content. Errors include fabricated case citations, misrepresented case law and false quotes, among other material.

The American Bar Association’s Formal Opinion 512, issued in 2024, said lawyers and law firms must “fully consider their applicable ethical obligations” and “have a duty of competence, including maintaining relevant technological competence” when using generative AI. That includes providing competent representation, maintaining confidentiality, communicating with their clients, guarding against errors in court and charging reasonable fees.

A Growing Divide: Can Solo and Small Firms Catch Up on AI?

If 2026’s survey results show how quickly Big Law and midsize firms have moved from AI discussion to deployment, then the year ahead may be a test of whether solos and small firms can close the gap with their larger peers.

Consider the safeguards firms are putting in place to reduce ethical risks. Only 26% of solo practitioners and 42% of firms with 2-19 lawyers have established clear policies around AI use on client matters. That compares to 80% of firms with 50-149 lawyers and 95% of firms with 150+ attorneys. Just one in three solos said they have trained on AI’s risks or are auditing their AI-generated work for accuracy.

In a September column for the ABA Journal, Alan Walter, a New Jersey-based practitioner, wrote about the burdens many small firms face when implementing AI tools. Formal Opinion 512 sets out a lengthy list of obligations for attorneys to run through, a task most larger firms have the resources to handle, Walter said. While the opinion espouses “the right principles,” he wrote, ethics rules do not “automatically translate into workable compliance frameworks” for smaller and solo firms.

As the survey suggests, resistance to AI may be futile. The question remains, however: Will the legal profession’s small practices be able to catch up, or will the gap between large and small firms become a chasm?

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David L. Brown is a legal affairs writer and consultant, who has served as head of editorial at ALM Media, editor-in-chief of The National Law Journal and Legal Times, and executive editor of The American Lawyer. He consults on thought leadership strategy and creates in-depth content for legal industry clients and works closely with Best Law Firms as senior content consultant.