Carlos Sylvestre Begnis (30 August 1903 – 22 September 1980) was a medical doctor and politician, born in Alto Grande, a village near Bell Ville, Córdoba province in Argentina. He was a rural physician and worked as a surgeon in hospitals of the city of Rosario, province of Santa Fe.
He entered politics through the Radical Civic Union. In 1958 he was elected governor of Santa Fe, following a period of de facto military rule (after the Revolución Libertadora, which had ousted president Juan Perón three years before). He became a part of the Intransigent Radical Civic Union (UCRI), and then formed part of the leadership of the Movement for Integration and Development (MID). His term was ended by a federal intervention.
In the 1970s, Sylvestre Begnis moved to the Justicialist Party (Peronism), and was elected governor again in 1973 (Argentina had just emerged from seven years of military dictatorship). The Hernandarias Subfluvial Tunnel, which joins Santa Fe and Entre Ríos under the Paraná River, was built during his administration, and then officially renamed after him and Entre Ríos governor Raúl Uranga. The Brigadier Estanislao López Highway, linking Rosario and Santa Fe (the two largest cities in the province), was also built at this time. Sylvestre Begnis followed the policies of desarrollismo, sponsored by the national government of president Arturo Frondizi, devoting a large share of the provincial budget to public works (schools, roads, electric power lines, hydraulic works).