The Roman Catholic Diocese of Floriano (Latin: Dioecesis Florianensis) is a suffragan Latin diocese in the ecclesiastical province of Teresina, in northeastern Brazil.

Its cathedral episcopal see is Cathedral São Pedro de Alcântara, dedicated to Peter of Alcantara, in the city of Floriano, Piauí state.

As per 2014, it pastorally served 162,100 Catholics (80.0% of 202,600 total) on 48,559 km in 29 parishes and 3 missions with 29 priests (14 diocesan, 15 religious), 31 lay religious (15 brothers, 16 sisters) and 7 seminarians.

• 27 February 2008: Established as Diocese of Floriano, on territory split off from the Diocese of Oeiras–Floriano (with its incumbent transferred as first bishop).

(all Roman rite)

Suffragan Bishops of Floriano

• Augusto Alves da Rocha (27 February 2008 - retired 17 March 2010), previously Bishop of Picos (Brazil) (1975.05.23 – 2001.10.24), Bishop of mother see Roman Catholic Diocese of Oeiras–Floriano (Brazil) (2001.10.24 – 2008.02.27)
• Valdemir Ferreira dos Santos (17 March 2010 – 4 May 2016), next Bishop of Amargosa (Brazil) (2016.05.04 – ...)
• Edivalter Andrade (2017.03.29 – ...), no previous prelature.

• List of Catholic dioceses in Brazil

• GCatholic.org, with Google map & satellite photo - data for all sections
• Catholic Hierarchy

6°46′03″S 43°01′19″W / 6.7676°S 43.0219°W / -6.7676; -43.0219