California

Patent attorneys in California

California hosts 9,567 active patent practitioners registered with the USPTO Office of Enrollment and Discipline. Patent attorneys and patent agents can both prepare and file patent applications, but only patent attorneys can also offer legal advice on prosecution strategy, freedom-to-operate analyses, and infringement opinions in California. Practitioners are concentrated across 20 cities, with the largest clusters in the metros listed below. Notable firms with multiple registered practitioners in the state include Hunter Industries, Leydig, Voit, and Mayer, and Finnegan, Henderson, Farabow, Garrett & Dunner, LLP.

Top cities in California

All practitioners in California

Michael J. Loi

Reg. 64451

Patent attorney

Hunter Industries

San Marcos, CA · 92078

760-591-7378

John B Loker

Reg. 66862

Patent attorney

Leydig, Voit, and Mayer

Walnut Creek, CA · 94596

925-482-0100

Haixia Long

Reg. 56222

Patent agent

Finnegan, Henderson, Farabow, Garrett & Dunner, LLP

Palo Alto, CA · 94304-1203

650-849-6617

Jonathan C. Long

Reg. 84721

Patent agent

Santa Clara, CA · 95053

949-554-8067

Michael A. Long

Reg. 59750

Patent attorney

Aexius, LLC

Rolling Hills Estates, CA · 90274-3800

310-625-3395

Xiang Long

Reg. 59525

Patent agent

Fremont, CA · 94536

650-521-3464

Robert R Longabaugh

Reg. 53234

Patent agent

Huntington Beach, CA · 92648

714-960-1036

Michael A Longo

Reg. 64172

Patent agent

Whittier, CA · 90601

562-695-1075

Anna M Longwell

Reg. 50629

Patent attorney

Palo Alto, CA · 94303

650-213-9162

Robert D Longwell

Reg. 53236

Patent attorney

Longwell & Associates

Palo Alto, CA · 94303-0064

650-213-9192

Sarah M Looff

Reg. 76937

Patent agent

Mountain View, CA · 94041

859-443-0444

Devin Lee Looijen

Reg. 64779

Patent attorney

Helix, Inc.

San Mateo, CA · 94401

844-211-2070

Vincent Look

Reg. 76392

Patent attorney

Womble Bond Dickinson LLP

Los Angeles, CA · 90025

424-369-2071

Gary L Loomis

Reg. 55403

Patent agent

G. L. Loomis & Associates, Inc.

Solana Beach, CA · 92075

858-259-9183

Timothy F Loomis

Reg. 37383

Patent attorney

Qualcomm, Inc.

San Diego, CA · 92121

858-845-8355

Valerie E Looper

Reg. 33007

Patent attorney

The Law Offices Of Valerie E. Looper

Vista, CA · 92084

410-804-7238

Brad J Loos

Reg. 51968

Patent agent

Kilpatrick Townsend & Stockton, LLP

Menlo Park, CA · 94025

650-324-6369

Eli A Loots

Reg. 54715

Patent attorney

Oakland, CA · 94611

510-684-6943

Rory R. Lootsma

Reg. 800104

Limited recognition

Knobbe Martens Olson & Bear, LLP

Irvine, CA · 92614

949-760-0404

Jorge A. Lopez

Reg. 55404

Patent agent

Downey, CA · 90242

856-577-3155

Margarita Lopez

Reg. 78083

Patent attorney

Lancaster, CA · 93534

661-609-6176

Miguel A. Lopez

Reg. 71507

Patent agent

Los Angeles, CA · 90067

310-229-9904

Theodore P Lopez

Reg. 44881

Patent attorney

Klein, O'Neill & Singh LLP

Irvine, CA · 92612

949-955-1920

Keila Lopez Arriaza

Reg. 902998

Limited recognition

University of San Francisco School of Law

San Francisco, CA · 94117-1080

415-827-8773

Andrea E. Lopez Giraldo

Reg. 84141

Patent agent

West Hills, CA · 91307

818-299-4428

Matthew Clay Loppnow

Reg. 45314

Patent attorney

Hickman Becker Bingham Ledesma LLP

Campbell, CA · 95008

408-414-1080

John E Lord

Reg. 56562

Patent attorney

Skiermont Derby LLP

Los Angeles, CA · 90071

213-788-4500

Todd A Lorenz

Reg. 39754

Patent attorney

Arnold & Porter LLP

San Francisco, CA · 94111

415-471-3295

D'Arcy H Lorimer

Reg. 53239

Patent agent

Lorimer Labs

Pismo Beach, CA · 93449

805-473-0659

Bradley K Lortz

Reg. 45472

Patent attorney

Canady & Lortz

Los Angeles, CA · 90010

626-292-7743

Common questions

Do I need a patent attorney based in California?

No. Every USPTO-registered patent practitioner is licensed to file applications on behalf of inventors in any state, regardless of where the practitioner's office is. Choosing a California-based practitioner can simplify in-person inventor signings, local meetings, and same-time-zone calls, but it is not a legal requirement.

How many patent attorneys are licensed in California?

9,567 active USPTO-registered patent practitioners list a California office address on the OEDCI roster. This includes both patent attorneys (who can also offer legal advice) and patent agents (who can prepare and file patents but not offer broader legal advice).

What is the difference between a patent attorney and a patent agent?

Both pass the USPTO Patent Bar and can prepare, file, and prosecute patent applications. Only patent attorneys also hold a state bar license, meaning they can additionally offer legal advice on infringement, licensing, and litigation strategy. Patent agents tend to charge less per hour and are common at large in-house IP departments.