Pierre-Constant Budin (November 9, 1846 – January 22, 1907) was a French obstetrician who was a native of Enancourt-le-Sec, a village in northwestern France.
In 1876 he earned his medical degree in Paris, and in 1882 became chief obstetrician at the Hôpital de la Charité. In 1895 he succeeded Étienne Stéphane Tarnier (1828-1897) as chair of obstetrics at the Hôpital Maternité. Budin was a member of the Académie de Médecine, and an officer of the Légion d'honneur.
Pierre Budin was a founder of modern perinatal medicine, and made many contributions in efforts to reduce infant mortality. He stressed the importance of proper nutrition and prevention of infectious disease in newborns, as well as education of new mothers on these subjects. Due to the problem of gastroenteritis in infants caused by contaminated cow's milk, Budin was a major proponent of breastfeeding, and believed in a substitution of sterilized milk if natural nutrition failed.
He also popularized a technique known as gavage for feeding premature infants who were too weak to receive nourishment by conventional methods.