California

Patent attorneys in California

California hosts 9,553 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 Orrick, Herrington & Sutcliffe LLP, Angius & Terry, LLP, and Weil. Gotshal and Manges LLP.

Top cities in California

All practitioners in California

Peter J O'Rourke

Reg. 53421

Patent attorney

Orrick, Herrington & Sutcliffe LLP

Menlo Park, CA · 94025

650-614-7400

Robert B O'Rourke

Reg. 46972

Patent attorney

Angius & Terry, LLP

Walnut Creek, CA · 94596

925-939-9933

Sean J. O'Rourke

Reg. 68883

Patent attorney

Weil. Gotshal and Manges LLP

Redwood Shores, CA · 94065

650-802-3909

Desmond P O'Sullivan

Reg. 67576

Patent attorney

O'Sullivan IP Law

SAN DIEGO, CA · 92122

619-890-5140

Garrett J O'Sullivan

Reg. 73556

Patent agent

San Diego, CA · 92121

858-598-4914

Katherine L O'Sullivan

Reg. 76957

Patent attorney

KIRKLAND & ELLIS LLP

Los Angeles, CA · 90067

213-680-8303

Eugene Oak

Reg. 35971

Patent attorney

Los Angeles, CA · 90005

213-365-2727

Naomi Obinata

Reg. 39320

Patent agent

SuVolta, Inc.

Los Gator, CA · 95032

408-429-6051

Tomas OBlonsky

Reg. 42045

Patent attorney

Anaheim, CA · 92807

714-282-7766

Michael M Obradovitch· II

Reg. 67747

Patent attorney

Obradovitch Law

Long Beach, CA · 90815

562-254-8362

Carlo Miguel C. Ocampo

Reg. 65328

Patent agent

Fenwick & West LLP

Mountain View, CA · 94041

650-335-7820

Mark R R Oda

Reg. 76659

Patent attorney

Baker Botts LLP

San Francisco, CA · 94111

628-291-6234

Paul C Oestreich

Reg. 44983

Patent attorney

NIWC Pacific

San Diego, CA · 92152-5001

801-870-1047

Marc P. Oettinger

Reg. 71529

Patent agent

Menlo Park, CA · 94026

650-857-5006

Michael Kyei Ofori

Reg. 80513

Patent attorney

KPPB LLP

Anaheim, CA · 92806

949-694-0666

Eric G. Ogawa

Reg. 65863

Patent agent

Burlingame, CA · 94010

510-333-1490

Joy M Ogawa

Reg. 42957

Patent attorney

Palo Alto, CA · 94306

650-856-1252

Richard Takashi Ogawa

Reg. 37692

Patent attorney

Ogava Professional Corporation

Palo Alto, CA · 94301

650-906-0323

Anne M. Ogle-Knee

Reg. 63911

Patent attorney

San Diego, CA · 92105

858-361-9172

Ian Bruce Oglesby

Reg. 60824

Patent agent

Cupertino, CA · 95014

650-867-1551

Brian D Ogonowsky

Reg. 31988

Patent attorney

Patent Law Group

Mountain View, CA · 94040

650-867-1596

Gregory D Ogrod

Reg. 30880

Patent attorney

Escondido, CA · 92026

760-749-7023

Chang-June J. Oh

Reg. 67293

Patent attorney

Medtronic MiniMed, Inc.

Northridge, CA · 91325

818-576-5089

David Y Oh

Reg. 46358

Patent agent

Cooley Godward, LLP

Palo Alto, CA · 94306

650-843-5779

Erik C Oh

Reg. 78101

Patent attorney

Corona, CA · 92878

949-705-7779

Euk Y Oh

Reg. 54345

Patent attorney

Codexis, Inc.

Redwood City, CA · 94063

650-421-8235

Minna M Oh

Reg. 56777

Patent attorney

USPS Employment Law Office - West

Long Beach, CA · 90802

562-628-1340

Richard K Oh

Reg. 73120

Patent agent

POK IP SERVICES INC

Irvine, CA · 92602

858-705-7723

Sung I Oh

Reg. 45583

Patent attorney

Chino Hills, CA · 91709

626-827-6204

Susie H Oh

Reg. 36391

Patent attorney

Sony Pictures Entertainment Inc.

Culver City, CA · 90232

310-244-8304

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?

9,553 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.