| 1991 South American Cross Country Championships | |
| Organisers: | CONSUDATLE |
| Edition: | 6th |
| Date: | February 2 |
| Host City: | Ambato, Tungurahua, Ecuador  |
| Nations Participating: | at least 2 |
| Races: | 6 |
| Distances: | 12 km – Senior men 8 km – Junior men (U20) 5 km – Youth men (U17) 8 km – Senior women 5 km – Junior women (U20) 3 km – Youth women (U17) |
| Previous: | 1990 Caracas |
| Next: | 1992 São Paulo |
The 1991 South American Cross Country Championships took place on February 2, 1991. The races were held in Ambato, Ecuador. Competitions open for youth athletes (under 17) were held for the first time.
Medal winners, and medal winners for junior and youth competitions were published.
All results are marked "affected by altitude" (A), because Ambato is situated at an elevation of about 2,600 m above sea level.
| Individual | |||||||
| Senior men (12 km) | Jacinto Navarrete | 41:37 A | Roberto Punina | 41:59 A | Néstor Quinapanta | 43:13 A | |
| Junior (U20) men (8 km) | William Roldán | 28:12 A | Carlos Collahuazo | 28:38 A | Julio Pozo | 29:12 A | |
| Youth (U17) men (5 km) | Patricio Rosero | 18:33 A | Pedro Yupa | 18:52 A | Bolívar Ordoñez | 19:00 A | |
| Senior women (8 km) | Graciela Caizabamba | 32:39 A | Soledad Villamarín | 32:57 A | Sandra Ruales | 33:11 A | |
| Junior (U20) women (5 km) | Carmen Naranjo | 20:00 A | Mónica Tapía | 20:07 A | Miriam Achote | 20:11 A | |
| Youth (U17) women (3 km) | Tania Cevallos | 11:27 A | Norma Torres | 11:29 A | Yolanda Duchi | 11:35 A |
Athletes from at least 2 countries participated.
(5) (at least 16)