CELAM
Pironio served as the Secretary-General of the Latin American Episcopal Council from 1967 to 1972. He also attended the Synod of Bishops from 29 September to 29 October 1967, and later attended the Second General Conference of the Latin American Episcopate from 24 August to 6 September 1968 in Colombia. He attended two additional synods in 1969 and in 1971. Pironio was elected as the President of the Latin American Episcopal Conference in 1972, served until 1974, and was confirmed for an extra year.