138 Mineola Boulevard, Mineola, New York 11501

Marc Gann

Founding Partner

516-294-0300 phone

516-294-0477 fax

Email Marc Gann ›

Marc Gann, Founding Partner


One of the most highly regarded trial lawyers in Nassau County

Marc Gann is one of the most highly regarded criminal defense lawyers on Long Island, and has handled countless high-profile cases across the New York metropolitan area. He handles criminal cases of all shapes and sizes, from simple traffic or DUI cases to the most serious major felonies.

Marc possesses particular experience defending murder and drug cases, including serious conspiracy matters in both New York state and federal courts, and has also taken verdicts on major felony cases including burglary, robbery and fraud.

An attorney respected by his peers

Marc Gann earns most of his clients via referral from other lawyers, court personnel or past clients. Martindale Hubbell also agrees that he is an attorney of the highest level of skill and ethics, having awarded him the AV rating.

Like his fellow partners, Marc Gann was a prosecutor in Nassau County for several years. He then spent several years in Baltimore handling criminal and civil cases before returning to New York to form Collins Gann McCloskey & Barry PLLC.

In addition to defending criminal cases, Marc also counsels sports nutrition companies and has litigated personal injury and other civil cases.

Giving back to the legal community

Marc has served as the President and been elected Director of the Nassau County Bar Association, and is a former chairman of the Criminal Courts Law and Procedure Committee of the Bar. This group honored him with the Association’s 2001 Directors’ Award for his contributions to the legal community.

He lectures to local and state bar associations as well as the National Institute of Trial Advocacy, and served as Team Leader for the 2002 National Institute of Trial Advocacy program at Hofstra University Law School. He is also a member of the Touro Law School faculty.

A Long Island criminal defense attorney ready to help

Like his partners at the Nassau County law firm Collins Gann McCloskey & Barry PLLC, Marc Gann can help you build the strongest possible defense for your criminal case. Contact them online or at 516-294-0300 today.

Practice areas

  • Commercial litigation
  • Regulatory law






Professional associations



Contact Form

We will respond to your inquiry in a timely fashion. Thank you.

Quick Contact Form