Mario Delgado


Mario Delgado Professional Corporation


Mario is routinely engaged as litigation counsel in respect of sophisticated and factually complex matters.  He has extensive experience defending claims involving class actions, products liability, municipal liability, professional indemnity, medical malpractice and construction.

Mario has a passion for advocacy and for providing clients with pragmatic solutions, uniquely tailored to the issues at hand.  He regularly appears in the Superior Court of Justice, the Divisional Court of Ontario, the Court of Appeal for Ontario and before regulatory bodies.

Mario’s representative work includes:

Class Actions

  • Representing clients across various industries, including health and medical devices, product failures, property losses, environmental issues and investor fraud
  • Providing risk litigation and management advise before a claim is issued
  • Advising on key issues relating to pre-certification procedures, certification, dismissal, discontinuance and settlement solutions


  • Acting in matters relating to development projects, pipelines, emissions, oil spills and soil contamination and contamination entering the water table
  • Defending claims involving spill and long-term pollution contamination events, particularly in the construction and energy sectors
  • Advising stakeholders in environmental matters and providing strategic advice in minimizing their risk exposure

Products Liability

  • Defending product liability disputes involving various commercial, industrial and dental products/materials and successfully responding to various allegations of deficiency: design, negligent or deficient manufacturing, negligent installation and failure to instruct on use of the product/material

Professional Indemnity

  • Representing inspectors, architects, engineers, dentists, teachers (and school boards), naturopaths, psychotherapists, optometrists, insurance brokers, paralegals and property managers, among others, in cases involving claims of alleged negligence in the performance of their professional responsibilities
  • Represented two design professionals at the Elliot Lake Inquiry that was commissioned to investigate the causes of the Algo Centre Mall collapse, which left 19 people injured and resulted in two deaths
  • Acted in a quasi-criminal matter relating to a claim of sexual assault arising from the administration of anesthetics during a surgical procedure

Medical Malpractice

  • Defending practitioners in civil proceedings and at various administrative tribunals, including involvement in matters arising from the failure to diagnose, provide reasonable treatment, obtain consent, carry out treatment in accordance with relevant standards and provide adequate post-operative care He routinely defends practitioners in cases involving allegations that the practitioner has failed to meet the standards expected by the regulatory body.

Construction Law

  • Defending all parties along the construction pyramid (general contractors, design professionals, subcontractors and suppliers) in claims arising from all stages of the construction process including, errors and omissions in design phase, bidding and tendering process, over-certification, lien claims, fee disputes, product liability and delay claims
  • Defending claims arising from all types of construction projects, including the design and construction of single residential homes, townhome developments, condominiums, industrial buildings, banks, medical buildings, commercial retail buildings, educational centers, recreational buildings, sporting arenas and medical buildings, among others

As part of the Whitelaw Twining’s management team, Mario is a dedicated mentor and diversity and inclusion advocate, helping shape the firm culture and the next generation of lawyers in the firm.

Outside of work, Mario loves spending time with his family.  An avid runner, he can be found training for the next marathon with his running group.

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LL.B., Osgoode, York University, 2006
H.B.A., York University, 2004

Professional Memberships & Affiliations

Called to the Ontario Bar in 2007