800 AM is a Mexican clear-channel frequency on which XEROK-AM in Ciudad Juárez is the dominant Class A station.

The station came on air in April 1965 as XEMMM-AM, named for its owner, Mario Marcos Mayans.

(The XEMMM calls were moved to a station Cadena Baja California then owned in Mexicali, now XEMMM-AM 940.)

ESPN Deportes Radio is now available in the San Diego-Tijuana border region on XESS-AM 620.

[2] It did not begin coming back on the air until April 2023, after the Cadena stations were sold to a consortium related to Tijuana news website Esquina 32.