O'Brien and Ryan, LLP - Attorneys at Law
Mary Ann Martillotti
Email: mmartillotti@obrlaw.com
Main: (610) 834-6246
Fax: (610) 834-1749
Assistant: Rachel Alvini
Email: ralvini@obrlaw.com
Main: (610) 834-6230

Mary Ann joined O'Brien & Ryan, LLP in 1994, and serves on its Management Committee. After starting her career as a judicial law clerk, Mary Ann became an Assistant District Attorney in Luzerne County where she gained invaluable trial experience prosecuting defendants in criminal jury trials. For the past twenty-seven years, Mary Ann has concentrated her practice on the defense of healthcare providers in professional liability matters. She has successfully tried medical malpractices cases to verdict as lead trial counsel in multiple venues, including Philadelphia County, Delaware County, Montgomery County and Bucks County, and has defended health care institutions and providers throughout Northeastern and Central Pennsylvania. Mary Ann has particular expertise handling high exposure cases involving catastrophically injured infants and adults, and has extensive experience mediating and arbitrating these complex matters. She routinely defends claims of corporate liability and/or systemic negligence against health care institutions. Her practice entails significant involvement and interaction with department heads of major health care institutions. Her clients have included physicians, nurses, mid-level providers, hospitals, substance abuse treatment facilities, health systems, universities, physician practice groups, and insurance companies. Mary Ann has defended physicians in a variety of medical specialties, including obstetrics and gynecology, neonatology, pediatrics, neurosurgery, cardiology, anesthesiology, genetics, radiology, gastroenterology, neurology, orthopedics, emergency medicine and cardiothoracic surgery.

Practice Areas:

Bar Admissions:

  • Pennsylvania, 1991
  • U.S. District Court Eastern District of Pennsylvania


  • The Dickinson School of Law, Carlisle, Pennsylvania, 1991, J.D.
  • King's College, Wilkes Barre, Pennsylvania, 1987, B.A.

Professional Associations and Memberships:

  • Philadelphia Area Society for Healthcare Risk Management
  • Pennsylvania Association of Healthcare Risk Management
  • Pennsylvania Bar Association
  • Montgomery County Bar Association

Classes/Seminars Taught:

  • Gynecology in the Courts, Grand Rounds, Thomas Jefferson University Hospital, Department of Obstetrics and Gynecology, October, 2019
  • Warning Fatigue Now a Matter of Criminal Liability: The Radonda Vaught Story, PAHCRM Quarterly Meeting, Omni Bedford Springs Resort, July, 2019
  • Peer Review After Reginelli, Are You Protected?, Double Tree Hotel, Plymouth Meeting PA, October 2018
  • EMTALA and Physician Peer Review, Analysis and Case Updates, Pennsylvania Associates for Health Care Risk Management (PAHCRM) Summer Education Day, July 2017
  • Mock Trial, Philadelphia Obstetrical Society, May 2017
  • Peer Review – For Whose Benefit Is It?  Philadelphia Bar Association, Medico-Legal Committee Meeting CLE, November 2016
  • Impact of Documentation on Pressure Ulcer Cases, Main Line Health, Riddle Annex, June 2016

Recent Representative Matters:

  • Non-pros obtained for neurosurgeon and hospital.
  • Dismissal of all claims against reproductive endocrinologist and hospital.
  • Non-pros obtained for radiologist and hospital.

Past Employment Positions:

  • Luzerne County Court of Common Pleas, Assistant District Attorney, 1992-1993
  • Honorable Peter J. O'Brien, Monroe County Court of Common Pleas, Judicial Law Clerk, 1991-1992

Hickory Pointe
2250 Hickory Rd, Suite 300
Plymouth Meeting, PA 19462
Phone: (610) 834-8800
Fax: (610) 834-1749