Recent commercial discoveries offshore Palawan have propelled the Philippines into the list of oil- and gas-producing countries, and have focussed on the importance of Miocene reefs as reservoirs. This new situation has motivated the update of earlier depositionnl-diagenetic models for the Miocene reefs in the Visayan Islands, which is presented in this paper. These reefs consisted of an association of corals, red algae, bryozoans, and encrusting foraminifers, which formed wave-resistant, constructed, barrier-and-atoll systems along the edge of narrow shelves, with associated back-reef patch reefs and frontal pinnacle reefs. The latter also grew on structural and depositional highs and platforms among deeper water carbonate mudstones and shales. Reservoirs developed in all the various types of buildups by extensive burial dissolution, often preceded (with the exception of some pinnacle reefs) by subaerial exposure generating secondary porosity by vadose to phreatic undersaturated dissolution. Seals were generally provided by overlying basinal carbonate mudstones and shales, and by andesitic volcaniclastics and basaltic lava flows. Source beds were mature, basinal, bituminous carbonate mudstones and shales, and migration of hydrocarbons was mainly updip, complicated by local structural conditions.