UFC Fight Night: Diaz vs. Neer, also referred to as Ultimate Fight Night 15, was held by the Ultimate Fighting Championship (UFC) on September 17, 2008 at the Omaha Civic Auditorium in Omaha, Nebraska.
The event was the lead-in to The Ultimate Fighter: Team Nogueira vs. Team Mir on Spike TV.
UFN 15 Picks and Predictions by N. Bailey
* This is Wilson Gouveia’s debut at middleweight from light heavyweight.
| Match | Winner | Loser | Method | Round | Time |
| 1 | Dan Miller | Rob Kimmons | Submission (Rear-naked choke) | 1 | 1:27 |
| 2 | Mike Massenzio | Drew McFedries | Submission (Kimura) | 1 | 1:28 |
| 3 | Jason Brilz | Brad Morris | TKO (Punches) | 2 | 2:54 |
| 4 | Joe Lauzon | Kyle Bradley | TKO (Punches) | 2 | 1:34 |
| 5 | Wilson Gouveia | Ryan Jensen | Submission (Armbar) | 2 | 2:04 |
| 6 | Alessio Sakara | Joe Vedepo | KO (Head kick and punch) | 1 | 1:27 |
| 7 | Eric Schafer | Houston Alexander | Submission (Arm-triangle choke) | 1 | 4:53 |
| 8 | Alan Belcher | Ed Herman | Decision (Split) | 3 | 5:00 |
| 9 | Clay Guida | Mac Danzig | Decision (Unanimous) | 3 | 5:00 |
| 10 | Nathan Diaz | Josh Neer | Decision (Split) | 3 | 5:00 |
UFC Fight Night 15 is what I have come to expect from a Fight Night event: decent fights of relatively little relevance. One notable quality of this card was the amount of previously relevant fighters now relegated to fighting in the prelims.