Margaret E. Billingham (née Macpherson) (September 20, 1930 - July 14, 2009) was a pathologist at Stanford University Medical Center, who made significant achievements in the early recognition and grading of transplant rejection following cardiac transplantation, known as 'Billingham's Criteria'.

Born in Tanzania, and educated in Kenya and subsequently qualified from the Royal Free Hospital in London, Billingham found herself developing rejection pathology and eventually becoming director of cardiac pathology at Stanford University Medical Center.

Moving to England, she gained admission to the Royal Free Hospital in London to study medicine, subsequently graduating in 1954.

[1] The grading system was soon adopted as the standard method for examining rejection and other cardiac diseases.

[6] In 1990, she became the first female president of the International Society for Heart and Lung Transplantation (ISHLT).

[3][4] Billingham not only devised the scoring system for acute heart transplant rejection based on endomyocardial biopsy samples at Stanford, but worked on getting it accepted internationally.

[1][3] Described by colleagues as “generous”, "kind", "gracious" and “reflective”, she was also known to advocate fellow female physicians.

[3][4] "Her contributions were the key to advancing the care and survival of heart transplant patients" – Robert Robbins, director of cardiovascular institute.