Tinos Diamantatos
As a seasoned trial lawyer and former federal prosecutor, Tinos Diamantatos is a Fellow of the American College of Trial Lawyers. Noted by Chambers USA as “an outstanding trial lawyer” who is “tremendous for clients and a good counselor,” Tinos represents organizations and individuals in trial work, litigation, government and internal investigations, and securities enforcement proceedings. This includes white collar crime, litigation related to government investigations, qui tam litigation, and complex civil litigation. In addition, he counsels clients on regulatory compliance issues. He also serves as deputy managing partner of the firm's Chicago office.
Listed as one of Crain’s Chicago Business “Notable Litigators and Trial Attorneys” for 2023, Tinos has tried more than 20 cases and achieved an outstanding record of success at trial. Tinos’ trial representations span jurisdictions in both federal and state courts throughout the United States and have involved complex civil and criminal matters. Included among his trial successes are two separate trial wins for a Fortune 10 company.
Tinos’ representations span several industry sectors, including the retail, pharmaceutical, healthcare, pharmacy, medical device, and financial services industries. He has handled investigations, the defense, and prosecutions of matters involving alleged healthcare fraud, commodities fraud, mortgage fraud, money laundering, bank fraud, wire fraud, mail fraud, and tax evasion. Tinos has also handled other complex matters involving terrorism, racketeering, extortion, corruption, obstruction, and civil rights violations.
Tinos serves as the deputy chair of the firm’s global white collar government investigations and sanctions practice. Tinos has been trusted by Fortune 500 companies, industry-leading pharmaceutical companies, healthcare companies, retail pharmacy chains, financial institutions, privately held businesses, and individuals in matters of utmost importance. Alongside members of the firm’s elite white collar team, Tinos helps clients navigate government investigations, regulatory minefields, and related white collar litigation throughout the United States and around the world.
Prior to joining Morgan Lewis, Tinos was a federal prosecutor at the US Attorney’s Office in Chicago where he successfully handled high-profile cases and trials that received national and international media attention. He also successfully served as lead appellate counsel representing the government on nine appeals before the US Court of Appeals for the Second Circuit and the US Court of Appeals for the Seventh Circuit. Tinos served in a number of sections within the Chicago US Attorney’s Office, including the Financial Crimes and Special Prosecutions Section, and the office’s Public Corruption and Organized Crime Section, where he completed his career as a prosecutor.
Tinos is a Fellow of the American College of Trial Lawyers, one of the premier, invitation-only legal associations in North America. He is also a former president of the prestigious Chicago Inn of Court, maintains an active pro bono practice, and is involved in multiple mentoring initiatives. Tinos is a former member of the John Marshall Law School Board of Trustees and has served as an adjunct trial advocacy professor for the law school, where he has also coached many successful trial teams competing at the national level. He also teaches, by invitation, law enforcement courses on trial techniques and investigative tactics to federal agents at their national training centers.
False Claims Act/Qui Tam Litigation
- Defending pharmaceutical companies in federal district court and state court in an action brought by a government entity alleging improper marketing of opioids. Recently successfully obtained dismissal of action.
- Defending ongoing FCA litigation for a national healthcare provider in federal district court following Department of Justice intervention on allegations related to improper physician billing.
- Defended pharmaceutical companies in multiple government investigations involving allegations related to off-label promotion and marketing practices.
Criminal Investigations
- Representing large financial institution in connection with a Department of Justice inquiry.
- Representing multiple individual physicians in connection with various federal investigations of alleged healthcare fraud and improper billing practices.
- Representing individual in a Department of Justice investigation into allegations of fraud and corruption.
Securities Fraud
- Representing a medical device manufacturer in connection with a Securities and Exchange Commission enforcement proceeding.
- Represented individual under investigation for alleged insider trading. Matter recently closed by the Securities and Exchange Commission with no adverse action taken.
Internal Investigations
- Conducted an internal investigation for multi-national corporation stemming from alleged violations of money laundering, structuring, and related financial reporting requirements.
- Conducted a variety of internal investigations of potential abuse and procurement fraud.
- Counseled clients on FCPA issues and compliance programs.
Commercial Litigation
- Defending a major financial institution in a class action involving allegations related to purported violations of state statutes.
- Defending a publicly-traded corporation in the managed services industry against allegations of contract fraud.
- DePaul University, 2000, B.S.
- John Marshall Law School, 2004, J.D., Cum Laude
- Illinois
- US Court of Appeals for the Second Circuit
- US Court of Appeals for the Seventh Circuit
- US District Court for the Northern District of Illinois Trial and General Bars
- Clerkship to Judge Charles P. Kocoras of the US District Court for the Northern District of Illinois

Fellow, American College of Trial Lawyers
Recognized, Notable Litigators and Trial Attorneys, Crain’s Chicago Business (2023)
Listed, The Best Lawyers in America, Criminal Defense: White-Collar, Chicago (2023–2026)
Ranked, Litigation: White-Collar Crime & Government Investigations, Illinois, Chambers USA (2021–2025)
Up and Coming, Litigation: White-Collar Crime & Government Investigations, Illinois, Chambers USA (2020)
Recommended, Dispute resolution: Corporate investigations and white-collar criminal defense, The Legal 500 US (2016, 2018–2025)
Named, Modern Healthcare’s “Largest Healthcare Firm” (2016–2021)
Recognized by Chicago Lawyer and Chicago Daily Law Bulletin as one of the Top 40 Under Forty lawyers in Illinois (2017)
Named, 2016 Emerging Lawyers’ Top Ten List (2016)
Recipient, Chicago Crime Commission's Mitch Mars Prosecutorial Excellence Award (November 2011)
Recipient, Chicago Crime Commission's Star of Distinction Criminal Justice Award (November 2010)
President, Chicago Inn of Court (2017–2018)
Member, Chicago Bar Association
Member, Federal Bar Association
Member, Seventh Circuit Bar Association
Member, American Bar Association
Member, Hellenic Bar Association
Member, The John Marshall Law School Board of Trustees
Member, Order of John Marshall
