The 2012 St. Petersburg Open was a tennis tournament played on indoor hard courts. It was the 17th edition of the St. Petersburg Open, and part of the ATP World Tour 250 Series of the 2012 ATP World Tour. It took place at the Petersburg Sports and Concert Complex in Saint Petersburg, Russia, from 17 September through 23 September 2012. Third-seeded Martin Kližan won the singles title.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Mikhail Youzhny | 29 | 1 | ||
| Denis Istomin | 34 | 2 | ||
| Martin Kližan | 46 | 3 | ||
| Fabio Fognini | 54 | 4 | ||
| Lukáš Lacko | 57 | 5 | ||
| Lu Yen-hsun | 59 | 6 | ||
| Guillermo García López | 68 | 7 | ||
| Jürgen Zopp | 71 | 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 loser:
Igor Andreev (right shoulder injury)
Pablo Andújar
Mikhail Kukushkin Andrey Kumantsov (dizziness)
Paolo Lorenzi (left Achilles tendon injury)
Jürgen Zopp (back injury)| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| Rajeev Ram |  Serbia | Nenad Zimonjić | 64 | 1 | ||
| Colin Fleming | Ross Hutchins | 69 | 2 | |||
 Czech Republic | František Čermák | Michal Mertiňák | 79 | 3 | ||
| Frank Moser | Ken Skupski | 134 | 4 |
The following pairs received wildcards into the doubles main draw:
Nikita Gudozhnikov Andrey Yakovlev / Alexander ZhurbinSee main article: 2012 St. Petersburg Open – Singles. 
Martin Kližan defeated Fabio Fognini, 6–2, 6–3It was Kližan's first title on the ATP World Tour.
See main article: 2012 St. Petersburg Open – Doubles.
Rajeev Ram / Nenad Zimonjić defeated Lukáš Lacko / Igor Zelenay 6–2, 4–6, [10–6]