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 Enuvis, International Flavors & Fragrances, Inc., and IP Attorney Services PC.

Top cities in California

All practitioners in California

Stefano Casadei

Reg. 51536

Patent agent

Enuvis

South San Francisco, CA · 94080

650-873-4625 X335

Amanda E. Casale

Reg. 76205

Patent agent

International Flavors & Fragrances, Inc.

Palo Alto, CA · 94304

858-314-1546

Emma E. Casamassima

Reg. 83031

Patent agent

Coronado, CA · 92118

619-438-2521

Cynthia A Casby

Reg. 47475

Patent attorney

IP Attorney Services PC

Burbank, CA · 91503

626-372-6428

Anthony Thomas Cascio

Reg. 29904

Patent attorney

Millbrae, CA · 94030-1905

650-703-3382

Dalton J Case

Reg. 80466

Patent attorney

Wilson Sonsini Goodrich & Rosati

San Diego, CA · 92130

858-350-2386

Robert E Case· III

Reg. 78495

Patent agent

DuPont Industrial Biosciences

Palo Alto, CA · 94304

650-656-5250

Steven Francis Caserza

Reg. 29780

Patent attorney

San Jose, CA · 95129

408-255-4163

Niall P Casey

Reg. 64137

Patent attorney

Carlsbad, CA · 92008

858-295-9290

Sean M Casey

Reg. 39514

Patent attorney

Sunset Beach, CA · 90742

714-955-9592

William J Casey

Reg. 65108

Patent attorney

Johnson & Johnson

Brisbane, CA · 94005

650-801-9873

Brian J Cash

Reg. 60546

Patent attorney

Steinfl & Bruno, LLP

Pasadena, CA · 91101

626-792-0536

Lindsey N Casillas

Reg. 65919

Patent attorney

Klinedinst PC

Sacramento, CA · 95814

916-444-7573

John Joseph Casparro

Reg. 29139

Patent agent

John J Casparro Patent Svcs

West Hills, CA · 91307

818-992-4067

Karen Marie Cassidy

Reg. 70611

Patent attorney

Knobbe Martens Olson & Bear LLP

Irvine, CA · 92614

949-721-5302

John J Cassingham

Reg. 34135

Patent attorney

Bio-Rad Laboratories INC

Hercules, CA · 94547

510-741-6092

Alexander B. Castanares

Reg. 80022

Patent agent

YHE Law LLP

Lafayette, CA · 94549

415-612-9636

Janet K Castaneda

Reg. 33228

Patent attorney

San Carlos, CA · 94070

650-637-1606

Steven R Castaneda

Reg. 67167

Patent attorney

Edwards Lifesciences

Irvine, CA · 92614

800-424-3278

Vianne M Castellano

Reg. 55040

Patent agent

South Pasadena, CA · 91030

626-308-8377

Kristin C Castle

Reg. 47208

Patent attorney

Oakland, CA · 94611

916-730-3130

Deborah L Caswell

Reg. 61766

Patent agent

Santa Clara, CA · 95051

408-420-6419

Thomas M Catale

Reg. 46434

Patent attorney

Murabito, Hao & Barnes, LLP

San Jose, CA · 95113

408-938-9060

Mark W Catanese

Reg. 64279

Patent agent

Dickinson Wright PLLC

San Diego, CA · 92130

858-397-7410

Michael A Catania

Reg. 36474

Patent attorney

Callaway Golf CO

Carlsbad, CA · 92008

760-930-8493

Andrew E. Cate

Reg. 69491

Patent attorney

Burbank, CA · 91505

415-314-8133

Richard B Cates

Reg. 36100

Patent attorney

Law Office of Richard B. Cates

Hermosa Beach, CA · 90254

310-318-6499

Kelvin B Catmull

Reg. 57535

Patent attorney

KILPATRICK TOWNSEND & STOCKTON LLP

Menlo Park, CA · 94025

650-326-2400

Amer Catovic

Reg. 72063

Patent agent

IP Tech

Carlsbad, CA · 92009

760-448-6346

Daniel M Cavanagh

Reg. 41661

Patent attorney

AvicenaTech Corp.

Sunnyvale, CA · 94089

714-458-2699

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.