The 1991 South American Cross Country Championships took place on February 2, 1991.

The races were held in Ambato, Ecuador.

[1] Competitions open for youth athletes (under 17) were held for the first time.

All results are marked "affected by altitude" (A), because Ambato is situated at an elevation of about 2,600 m above sea level.

*   Host nation (Ecuador)Athletes from at least 2 countries participated.