| Jurisdiction: | Diocese |
| Piedras Negras | |
| Latin: | Dioecesis Saxanigrensis |
| Local: | Diócesis de Piedras Negras |
| Country: | Mexico |
| Province: | Province of Monterrey |
| Area Sqmi: | 21,864 |
| Population: | 550,000 |
| Population As Of: | 2004 |
| Catholics: | 440,000 |
| Catholics Percent: | 80 |
| Parishes: | 26 |
| Denomination: | Catholic Church |
| Sui Iuris Church: | Latin Church |
| Rite: | Roman Rite |
| Established: | 8 January 2003 (years ago) |
| Cathedral: | Cathedral of the Martyrs of Christ the King |
| Bishop: | Alonso Gerardo Garza Treviño |
| Metro Archbishop: | Rogelio Cabrera López |
| Map: | Roman Catholic Diocese of Piedras Negras in Mexico.jpg |
The Diocese of Piedras Negras (Latin: Dioecesis Saxanigrensis) is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Mexico. It is a suffragan in the ecclesiastical province of the metropolitan Archdiocese of Monterrey. The diocese was erected on 8 January 2003. Its cathedra is found within the Catedral Mártires de Cristo Rey in the episcopal see of Piedras Negras, Coahuila.