He received his episcopal consecration on the following 28 October from Cardinal Pietro Fumasoni Biondi, with Archbishops Giuseppe Pizzardo and Carlo Salotti serving as co-consecrators.

Riberi was later named nuncio to the African missions dependent of the Sacred Congregation for the Propagation of the Faith on 4 November of that same year.

[3] Chinese authorities arrested Riberi on allegations of colluding with American intelligence and false accusations of participating in a plot to kill Mao Zedong.

[1]: 184  Riberi stayed in Hong Kong for two years, and after lobbying from the Republic of China (ROC), Bishop Yu Bin, and Cardinal Francis Spellman, moved his nunciature to Taipei.

He was created cardinal-priest of San Girolamo della Carità by Pope Paul VI in the consistory of 26 June 1967, but died some months later in Rome, at age 70.