Primary productivity data from 6 cruises in the Gulf of California are summarized. A total of 31 stations with 133 samples was available. The Gulf of California represents a subtropical area with exceptionally high rates of primary productivity. This fact may be accounted for by temporary seasonal upwelling, a wind-mixed water column down to the shallow thermocline, especially in the northern part of the Gulf, and by tidal mixing, especially in the Ballenas Channel between Baja California and the island Angel de la Guardia. Rates of primary productivity in the Gulf of California are comparable to those in areas such as the Bay of Bengal, the upwelling areas off the west coast of Baja California, or North Africa. They are about 2 to 3 times greater than that in the open Atlantic or the open Pacific at similar latitudes.