| Date: | August 3 – August 9 |
| Edition: | 21st |
| Location: | City of San Marino, San Marino |
| Champs: |  Andreas Seppi |
| Champd: |  Lucas Arnold Ker / Sebastián Prieto |
The 2009 San Marino CEPU Open was a professional tennis tournament played on outdoor red clay courts. It was the twenty-first edition of the tournament which was part of the Tretorn SERIE+ of the 2009 ATP Challenger Tour. It took place in City of San Marino, San Marino between 3 and 9 August 2009.
| Nationality | Player | Ranking* | Seeding | |
|---|---|---|---|---|
| Italy | Andreas Seppi | 43 | 1 | |
 Spain | Óscar Hernández | 72 | 2 | |
| Björn Phau | 78 | 3 | ||
 Romania | Victor Crivoi | 81 | 4 | |
 Austria | Daniel Köllerer | 82 | 5 | |
| Spain | Daniel Gimeno-Traver | 86 | 6 | |
 Belgium | Olivier Rochus | 87 | 7 | |
| Spain | Alberto Martín | 100 | 8 |
The following players received wildcards into the singles main draw:
The following players received a Special Exempt into the main draw:
The following players received entry from the qualifying draw:
See main article: 2009 San Marino CEPU Open – Singles. Andreas Seppi def. Potito Starace, 7–6(4), 2–6, 6–4
See main article: 2009 San Marino CEPU Open – Doubles. Lucas Arnold Ker / Sebastián Prieto def. 
Johan Brunström / Jean-Julien Rojer, 7–6(4), 2–6, [10–7]
