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 Cislo & Thomas LLP, Cislo and Thomas LLP, and Jones Day.

Top cities in California

All practitioners in California

Daniel M Cislo

Reg. 32973

Patent attorney

Cislo & Thomas LLP

Los Angeles, CA · 90025

310-451-0647

Donald M Cislo

Reg. 22060

Patent attorney

Cislo and Thomas LLP

Los Angeles, CA · 90025

310-451-0647

Harve Eliott Citrin

Reg. 27977

Patent attorney

Palo Alto, CA · 94303

650-327-0829

James C Ciula

Reg. 58064

Patent agent

Jones Day

Palo Alto, CA · 94303

650-687-4193

Brian C Claassen

Reg. 63051

Patent attorney

Knobbe Martens Olson & Bear LLP

Irvine, CA · 92614

949-760-0404

Marie L. Clapp

Reg. 68724

Patent agent

Chevron Corp.

San Ramon, CA · 94583

925-842-6455

Ricardo J Claps

Reg. 65796

Patent agent

McDermott Will & Emery

Menlo Park, CA · 94025

650-815-7465

Jeremy Dylan Clar

Reg. 52751

Patent attorney

US District Court

Fresno, CA · 93721

559-499-5799

Megan M. Clarey

Reg. 63966

Patent agent

Morrison & Foerster LLP

San Francisco, CA · 94105

415-268-6494

David L. Clark

Reg. 59502

Patent agent

Wilson Sonsini Goodrich & Rosati, PC

San Diego, CA · 92130

858-350-2300

Douglas L Clark

Reg. 68443

Patent attorney

Arnold & Porter

Los Angeles, CA · 90017-5844

213-243-4008

Gary Alan Clark

Reg. 28060

Patent attorney

Sheppard, Mullin, Richter & Hampton LLP

Los Angeles, CA · 90071

213-617-4197

Jared R Clark

Reg. 62062

Patent attorney

IP Agility (JC Consulting)

San Jose, CA · 95113

747-202-5322

Jeffrey S Clark

Reg. 75618

Patent attorney

Andreessen Horowitz

Menlo Park, CA · 94025

617-767-3177

Kevin M. Clark

Reg. 68320

Patent agent

Genentech, Inc.

South San Francisco, CA · 94080

650-255-8680

Kevin J Clark

Reg. 42421

Patent attorney

Silicon Edge Law Group, LLP

Pleasanton, CA · 94566

925-621-2110

Melody E. Clark

Reg. 51566

Patent agent

Arena Pharmaceuticals, Inc.

San Diego, CA · 92121

858-453-7200

Ronald James Clark

Reg. 21058

Patent attorney

Newport Beach, CA · 92658

949-673-7574

Brian T Clarke

Reg. 45552

Patent attorney

Accuray, Inc.

Sunnyvale, CA · 94089

408-789-4426

Pauline Ann Clarke

Reg. 29783

Patent attorney

Los Altos, CA · 94022

650-917-8244

Richard D Clarke

Reg. 38846

Patent attorney

LAW OFFICE OF RICHARD D. CLARKE

La Mesa, CA · 91941-7301

619-823-3652

Gregory K. Clarkson

Reg. 72581

Patent attorney

Stetina Brunda Garred & Brucker, PC

Aliso Viejo, CA · 92656

949-855-1246

Cameron D. Clawson

Reg. 73509

Patent attorney

Quinn Emanuel Urquhart & Sullivan, LLP

Redwood Shores, CA · 94065

650-801-5000

Allan B Claybon

Reg. 65797

Patent attorney

Messner Reeves LLP

Los Angeles, CA · 90025

424-276-6214

James P Cleary

Reg. 45843

Patent attorney

Mintz, Levin, Cohn, Ferris, Glovsky,

San Diego, CA · 92130

858-314-1500

Robert R. Cleary· Jr.

Reg. 60003

Patent attorney

Wilson Sonsini Goodrich & Rosati PC

Palo Alto, CA · 94304-1050

650-849-3252

Richard A Clegg

Reg. 33485

Patent attorney

Law Office of Richard Clegg

San Diego, CA · 92101

619-400-4920

Ken Clements

Reg. 77382

Patent agent

Los Gatos, CA · 95033

408-353-5027

Michael G Cleveland

Reg. 46030

Patent agent

Davis Wright Tremaine, LLP

San Francisco, CA · 94111-6533

415-276-6500

Carey J. Cling

Reg. 83011

Patent agent

Wilson Sonsini

San Diego, CA · 92130

858-350-2300

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.