The company did not provide further comment on the likely duration of the idle, but said it intends to return the plant to normal operations once demand levels support doing so.
The Martinez plant is the second in the United States and third in North America to temporarily cease operations in response to the plummeting demand for products such as gasoline and jet fuel amid severe travel restrictions in place to help slow the spread of the coronavirus.
Marathon previously announced it would idle its 26,000 bpd refinery in Gallup, New Mexico.
North Atlantic Refining has also idled its 130,000 bpd refinery in Come-by-Chance, Canada.
U.S. demand for gasoline has fallen by about a third due to the coronavirus pandemic, which has upended daily life and prompted stay-at-home orders for most of the country, according to the U.S. Energy Information Administration.
As a result, refiners have slashed output and seen gasoline profit margins fall to the lowest since 2008.