The 2012 Open Castilla y León was a professional tennis tournament played on hard courts. It was the 27th edition of the tournament which was part of the Tretorn SERIE+ of the 2012 ATP Challenger Tour. It took place in Segovia, Spain between 21 and 27 August 2012.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Spain | Daniel Gimeno Traver | 110 | 1 | |
| Spain | Daniel Muñoz de la Nava | 126 | 2 | |
 Serbia | Dušan Lajović | 138 | 3 | |
 Russian Federation | Evgeny Donskoy | 142 | 4 | |
| Russian Federation | Konstantin Kravchuk | 207 | 5 | |
 France | Kenny de Schepper | 214 | 6 | |
 Argentina | Facundo Argüello | 229 | 7 | |
| Spain | Iván Navarro | 239 | 8 |
The following players received wildcards into the singles main draw:
Andrés Artuñedo Martínavarr Carlos Benito Hergueta Jorge Hernando Ruano Ricardo Villacorta-AlonsoThe following players received entry from the qualifying draw:
See main article: 2012 Open Castilla y León – Singles.
Evgeny Donskoy def. Albano Olivetti, 6–1, 7–6(13–11)See main article: 2012 Open Castilla y León – Doubles.
Stefano Ianni / 
Florin Mergea def. Konstantin Kravchuk / 
Nikolaus Moser, 6–2, 6–3