The 2005 Copa Petrobras Santiago was a professional tennis tournament played on outdoor red clay courts. It was part of the 2005 ATP Challenger Series. It took place in Santiago, Chile between 24 and 30 October 2005.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Spain | Fernando Vicente | 96 | 1 | |
| Spain | Óscar Hernández | 100 | 2 | |
 Argentina | ||||
 Brazil | Flávio Saretta | 115 | 4 | |
| Boris Pašanski | 118 | 5 | ||
 Austria | Oliver Marach | 123 | 6 | |
| Juan Antonio Marín | 125 | 7 | ||
| Spain | Rubén Ramírez Hidalgo | 129 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
The following players received entry as lucky losers:
Carlos Berlocq (right shoulder injury) → replaced by Adrian Cruciat Marcos Daniel (back injury) → replaced by Alexandre SimoniSee main article: 2005 Copa Petrobras Santiago – Singles. Júlio Silva def. Rubén Ramírez Hidalgo, 6–2, 6–3
See main article: 2005 Copa Petrobras Santiago – Doubles. Daniel Köllerer / Oliver Marach def. Lucas Arnold Ker / 
Giovanni Lapentti, 6–4, 6–3
