Client Service philosophy

The Leff & Cohen, Ltd. Client Service Philosophy guides our team to provide the highest quality of personalized wealth and estate planning services together with objective legal advice for meeting the needs of our diverse client base.

Our History

Leff & Cohen, Ltd. was founded in September 1991 as the successor to a firm originally formed in 1964 by Aaron Cohen.  Sherwin H. Leff joined the predecessor firm in 1967. Leff & Cohen, Ltd. provides a wide range of general business and tax services primarily to entrepreneurial individuals and their business interests. The firm represents clients who conduct business within regional, national and international sectors. Our diverse client base includes general business corporations, professional and close corporations, governmental entities, not-for-profit organizations, limited liability companies (LLCs), partnerships (general, limited and limited liability/LLPs) and individuals.

Meet the Team

Each member of The Leff & Cohen, Ltd. team is a recipient of either a Leading Lawyer or Emerging Lawyer award.
Our lawyers are client service relationship professionals ready to assist you.

sherwin h. leff

Sherwin H. Leff, was admitted to the Illinois Bar in 1967. He received a B.S. in Accounting from the University of Wisconsin in 1962 and his J.D. from John Marshall Law School in 1967. He passed the certified public accounting examination in Illinois. His prior experience includes the Internal Revenue Service and public accounting. Practice specialties include representing owners of closely held business entities and their ongoing operations, representation of high net worth individuals in sophisticated estate planning, probate, income and estate taxation, purchase and sale of businesses and commercial real estate, insurance planning, and real estate tax assessment reduction and appeals.


Aaron Cohen 
vice President & Founder

Aaron Cohen was admitted to the Illinois Bar in 1956. He earned his B.S. in 1951 and J.D. in 1956 from the University of Illinois Urbana-Champaign. He passed the certified public accountant examination in Illinois. Practice specialties include commercial law transactions, income and estate taxation and estate planning.  Prior experience in public accounting, at the Securities and Exchange Commission and as an Assistant U.S. Attorney. He has taught taxation at John Marshall Law School and Kent College of Law and business law and Corporation finance at Roosevelt University and at the University of Illinois, College of Commerce, in Urbana-Champaign. He has delivered numerous presentations on tax topics and estate planning to banks, trade associations and public accountants.


Robert C. Ansani was admitted to the Illinois Bar in 1999. He received his B.S. Business Administration from the University of Arizona and J.D. and Taxation LL.M. degrees from John Marshall Law School. He is a registered certified public accountant in Illinois and Arizona. He is a licensed Life and Health Insurance Producer (Illinois) and a licensed Real Estate Broker (Illinois). Practice concentrations include estate planning, administration and litigation, business law, tax, real estate, employment issues, governmental regulation, commercial litigation, and non-profit administration.


Ronald G. Glosniak

Ronald G. Glosniak was admitted to the Illinois Bar in 1975. He earned his B.A., Cum Laude, Loyola University in 1972 and J.D. in 1975 from Loyola University School of Law. With over thirty-five years’ experience, his practice specialty is in real estate assessment/taxation. He has made numerous appearances before the administrative tax agencies (Assessor and Board of Appeals) and tax cases handled in the Circuit Court system. His representation includes real estate taxpayers and properties in various outlying counties while appearing before the local Boards of Review as well as the Illinois Property Tax Appeal Board.

Michael G. Glosniak

Michael G. Glosniak was admitted to the Illinois Bar in 2006. He received his B.S. in 2003 from the University of Notre Dame and J.D. in 2006 from Chicago-Kent College of Law. Practice concentrated primarily in real estate tax assessment, commercial and real estate transactions, estate administration, and probate.

Our Leading Lawyers are available for consultation.
Call 312-782-2700 to schedule an appointment.