The San Marcos Stakes is an American Grade III Thoroughbred horse race held annually in late January or early February at Santa Anita Park in Arcadia, California.
Open to horses aged four and older, it is raced on turf over a distance of one and one-quarter miles.
Inaugurated in 1952 as a one-mile race on dirt, in 1954 it was changed to one and one-quarter miles and became Santa Anita Park's first graded stakes race on turf.
Run as handicap prior to 2000, it is now raced under allowance weight conditions, with specified weight reductions for horses who meet certain conditions.
There was no race held in 1970 and for 1978 it was set at a distance of 1 and one-eighth miles.