The 2013 ATP Vegeta Croatia Open Umag was a men's tennis tournament played on outdoor clay courts. It was the 24th edition of the ATP Vegeta Croatia Open Umag, and was part of the ATP World Tour 250 Series of the 2013 ATP World Tour. It took place at the International Tennis Center in Umag, Croatia, from 18 July until 28 July 2013. Fifth-seeded Tommy Robredo won the singles title.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 France | Richard Gasquet[1] | 9 | 1 | |
 Italy | Andreas Seppi | 24 | 2 | |
| Italy | Fabio Fognini | 25 | 3 | |
 Ukraine | Alexandr Dolgopolov | 26 | 4 | |
 Spain | Tommy Robredo | 29 | 5 | |
 Slovakia | Martin Kližan | 38 | 6 | |
| Florian Mayer | 45 | 7 | ||
 Argentina | Carlos Berlocq | 46 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
Jerzy Janowicz (right arm injury) Fernando Verdasco (hand injury)
Andreas Haider-Maurer (lower back strain) Horacio Zeballos (intercostal muscle pain)| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
 Czech Republic | František Čermák | Czech Republic | Lukáš Dlouhý | 81 | 1 | |
| Andre Begemann | Martin Emmrich | 86 | 2 | |||
 United States | Nicholas Monroe | Simon Stadler | 122 | 3 | ||
| Poland | Tomasz Bednarek | Poland | Mateusz Kowalczyk | 133 | 4 |
The following pairs received wildcards into the doubles main draw:
The following pair received entry as alternates:
Fabio Fognini (fatigue)
Viktor Troicki (personal reasons) Horacio Zeballos (intercostal muscle pain)See main article: 2013 ATP Vegeta Croatia Open Umag – Singles.
Tommy Robredo defeated Fabio Fognini, 6–0, 6–3See main article: 2013 ATP Vegeta Croatia Open Umag – Doubles.
Martin Kližan / David Marrero defeated Nicholas Monroe / Simon Stadler, 6–1, 5–7, [10–7]