Illinois

Patent attorneys in Illinois

Illinois hosts 2,917 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 Illinois. 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 McDonnell Boehnen Hulbert & Berghoff LLP, Lindsay Law, LLC, and Quarles & Brady LLP.

Top cities in Illinois

All practitioners in Illinois

Erica D. Lindsay

Reg. 73437

Patent attorney

Lindsay Law, LLC

Chicago, IL · 60615

312-380-1618

John R Linzer

Reg. 56972

Patent attorney

Quarles & Brady LLP

Chicago, IL · 60606

312-715-5059

Isabel Victoria Kats Liokumovich

Reg. 84633

Patent agent

Chicago, IL · 60607

847-922-6695

Peter J. Lish

Reg. 59383

Patent attorney

McAndrews, Held & Malloy LTD

Chicago, IL · 60661

312-775-8000

Stephen A Litchfield

Reg. 29941

Patent attorney

Schneider Electric USA, Inc.

Palatine, IL · 60067

847-925-3516

Adam V. Litteken

Reg. 72076

Patent attorney

Ladas & Parry LLP

Chicago, IL · 60604

312-427-1300

Benjamin P Liu

Reg. 61703

Patent attorney

Chicago, IL · 60637

857-389-1039

Dan Liu

Reg. 78847

Patent attorney

Crowell & Morning LLP

Chicago, IL · 60611

312-840-3267

Guoquan Liu

Reg. 67514

Patent agent

Department of Pharmacology

Chicago, IL · 60612

Kevin B Liu

Reg. 77002

Patent attorney

Leydig, Voit & Mayer

Chicago, IL · 60601

312-616-5606

Shuang Liu

Reg. L1405

Limited recognition

Marshall, Gerstein & Borun LLP

Chicago, IL · 60606

312-423-3457

Yonglin Liu

Reg. 68710

Patent agent

K&L Gates LLP

Chicago, IL · 60602

312-807-4316

Yutong Liu

Reg. 902879

Limited recognition

Northwestern Pritzker School of Law

Chicago, IL · 60611

312-900-3029

Justin R. Lizalek

Reg. 82684

Patent attorney

Hanley, Flight & Zimmerman, LLC

Chicago, IL · 60606

312-676-1746

Wan-Shoon Lo

Reg. 71076

Patent attorney

McDermott Will & Emery, LLP

Chicago, IL · 60606

312-984-5810

Matthew E. Loar

Reg. 84550

Patent attorney

Loar Law

Chicago, IL · 60606

224-434-5627

Alexander M. Lodge

Reg. 79562

Patent attorney

AbbVie Inc.

North Chicago, IL · 60064

847-936-6747

Eric L Lohrenz

Reg. 46016

Patent attorney

Jenner & Block, LLP

Chicago, IL · 60654-3456

312-923-8313

Ronan P Lonergan

Reg. 78665

Patent agent

Banner & Witcoff, Ltd.

Chicago, IL · 60606

312-463-5484

Lauren N. Long

Reg. 81364

Patent agent

Foley & Lardner

Chicago, IL · 60611

630-240-2216

Thomas J. Loos

Reg. 60161

Patent attorney

Downers Grove, IL · 60516

708-574-6466

Erick I. Lopez

Reg. 77286

Patent attorney

Berwyn, IL · 60402

708-271-5361

Bradley P. Loren

Reg. 82885

Patent attorney

McAndrews, Held & Malloy

Chicago, IL · 60661

312-775-8009

Logan C Lorson

Reg. 82305

Patent attorney

Caterpillar Inc.

Peoria, IL · 61629

972-228-5502

Anne V Lotsoff

Reg. 40765

Patent attorney

Hinsdale, IL · 60521

630-325-5054

Caroline S. Lourgos

Reg. 75202

Patent agent

Chicago, IL · 60661

309-840-0374

James L Lovsin

Reg. 69550

Patent attorney

McDonnell Boehnen Hulbert & Berghoff LLP

Chicago, IL · 60606

312-913-0001

Peter E. Loy

Reg. 79189

Patent agent

Banner Witcoff

Chicago, IL · 60606

312-463-5469

Alexander Lu

Reg. 82034

Patent agent

McDonnell Boehnen Hulbert & Bergoff LLP

Chicago, IL · 60606

312-913-2142

Jerry Y Lu

Reg. 79950

Patent agent

McDonnell Boehnen Hulbert & Berghoff LLP

Chicago, IL · 60606

312-913-2011

Common questions

Do I need a patent attorney based in Illinois?

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 Illinois-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 Illinois?

2,917 active USPTO-registered patent practitioners list a Illinois 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.