Photo of Mary Schaerdel Dietz

Mary Schaerdel Dietz Senior Counsel

Areas of Practice


Bar Admissions

  • Texas

Court Admissions

  • Supreme Court of Texas
  • U.S. Court of Appeals, Fifth Circuit
  • U.S. District Court, Western District of Texas
  • U.S. District Court, Southern District of Texas
  • U.S. District Court, Northern District of Texas
  • U.S. District Court, Eastern Distict of Texas


Baylor University School of Law, J.D., cum laude, 1982

Texas Woman's University, B.S., with honors, 1972

Mary Dietz advises clients on commercial litigation matters. She has handled high-profile cases and is well-versed in multiple areas of commercial and business litigation, such as the Texas Deceptive Trade Practices Act, construction law, contract law, open records act issues, administrative law and mediation. Her mediation schedule is available online.


Mary Dietz was one of the first female civil litigators in Waco, Texas, where she tried more than 22 jury cases in her first three years of practice. In her more than 33 years of legal practice, she has handled cases in Texas and across the United States.

Recently, she has been involved in multimillion dollar class action suits, contract claims in arbitration, sanctions for filing a frivolous lawsuit, and cases involving the theft of trade secrets and breach of non-competition agreements. She has handled arbitration disputes, is a trained and recognized mediator (for over 15 years) and has handled many regulatory matters for clients with state agencies and boards.

Mary Dietz has extensive experience in extraordinary remedy practice, specifically in injunctions and garnishments. She has given CLE speeches and prepared written papers on injunctions and extraordinary remedies, as well as other subjects such as sanctions and professionalism.

Before joining Cox Smith, Mary Dietz was a partner in a large international law firm for more than 15 years, handling complex litigation cases, heading the firm's litigation section mentoring program, and co-coordinating the work-life balance program.

Her experience includes the following:

  • Represented national health services client in hospital lease dispute with doctors (involving injunctive relief)
  • Represented software company in defending theft of trade/secret claims
  • Represented national health care provider in Open Records Act Dispute with State of Texas
  • Represented national insurance provider in class action cases brought by its agents
  • Obtained injunctive relief for landowners in air space rights dispute with adjoining land owner/developer
  • Obtained injunctive relief in theft of trade secret/breach of contract matter for health plan provider against former general agent for gaining unauthorized access to client's restricted website
  • Represented health care provider in contract dispute with hospital group
  • Represented security provider in enforcing non-competition agreement (injunction)
  • Represented equipment rental company in Water Act violation dispute
  • Represented construction company in breach of contract claim in arbitration
  • American Board of Trial Advocates (ABOTA), since 1995
      • Tex-ABOTA, President 2013 
      • Austin ABOTA Chapter: President 2007-2010; past membership chair, 2004-2005; vice president, 2005-2007
  • Austin Bar Association
    • Board of Directors (former)
    • Judicial Affairs Committee, co-chair, 2014-2015
    • Bench Bar Committee, past co-chair
    • Diversity in the Profession Committee
    • Continuing Legal Education Committee
    • Bar & Grill Finance Committee, past chair
    • State Bar of Texas Administration Rules of Evidence Committee
    • 2015 ABA Equal Justice Conference Host Committee
  • Association of Attorney-Mediators
  • State Bar of Texas, State Bar Federal Laws and Regulations Affecting the Bar Committee (former)
  • 2004 5th Circuit Judicial Conference, committee co-chair
  • Travis County Settlement Week, mediator (former)
  • Austin Bar Foundation, Director (former)
  • Robert W. Calvert Inns of Court, Master (former)
  • The Center for Women in Law Annual Leadership Boot Camp Faculty
  • State Bar of Texas 2014 Annual Meeting Committee 2009-2010

Community/Civic Activities

  • Austin Chamber of Commerce, Legislative Committee (former) 
  • Member, Real Estate Council of Austin (RECA); serving on Regional Issues & Transportation subcommittees (former)
  • Volunteer, Mobile Loaves and Fishes
  • Recognized in The Best Lawyers in America®  for Commercial Litigation, Litigation - Banking and Finance, Litigation - Construction, and Litigation - Real Estate 2006-PresentCopyright 2015 by Woodward/White, Inc., Aiken, SC
  • Recognized in Texas Super Lawyers® for Business Litigation, 2005-2015
  • Martindale-Hubbell® AV® PreeminentTM Peer Review Rating for more than 15 years