The San Benito Formation is a Katian geologic formation of central Bolivia. The formation belongs to the Cochabamba Group, overlies the Anzaldo Formation and is overlain by the Cancañiri Formation. The 500 metres (1,600 ft) thick formation comprises a succession of shallow water quartzitic sandstones with minor interbeds of dark grey micaceous siltstones. Shelly fossils have been found at few horizons and consist mainly of linguliformean brachiopods, bivalves, and a few homalonotid trilobite remains. Poorly preserved graptolites occur occasionally in the shaly beds.

The formation has provided the following fossils:

• List of fossiliferous stratigraphic units in Bolivia

• J. L. Benedetto. 2013. Upper Ordovician Brachiopods from the San Benito Formation, Cordillera del Tunari, Bolivia. Ameghiniana 50(4):418-428
• R. Suárez Soruco. 1976. El sistema ordovícico en Bolivia. Revista Tecnica YPF Bolivia 5(2):111-123