| 01 | Pruett / Rojas / Franchitti / Montoya | TELMEX Chip Ganassi with Felix Sabates (USA) | Mike Hull | Riley | Mk XI | Lexus | DP |
| 02 | Dixon / Wheldon / Duran / Lloyd | Target Chip Ganassi with Felix Sabates (USA) | Mike Hull | Riley | Mk XI | Lexus | DP |
| 06 | Reese / Nearn / Pilgrim / Bunting / Edwards | Banner Racing (USA) | Leighton Reese | Pontiac | GXP.R | Pontiac | GT |
| 07 | Edwards / Collins / Magnussen | Banner Racing | Leighton Reese | Pontiac | GXP.R | Pontiac | GT |
| 08 | Goldin / Goldin / Meassick | Goldin Brothers Racing | Steve Goldin | Mazda | RX-8 | Mazda | GT |
| 09 | Cosmo / Camirand / McDowell | Spirit of Daytona Racing | Troy Flis | Fabcar | FDSC/03 | Porsche | DP |
| 2 | Zogaib / McNish / Luhr / Rockenfeller | SAMAX | Peter Baron | Riley | Mk XI | Pontiac | DP |
| 3 | Shane Lewis | Southard Motorsports | Steve Southard | Riley | Mk XI | Lexus | DP |
| 6 | Pew / James / Allmendinger / Frisselle | Michael Shank Racing | Michael Shank | Riley | Mk XX | Ford | DP |
| 7 | Plumb / Wahl / Grégoire / Cullen / Shovlin | Fortune Market Racing | Emmanuel Lupe | Riley | Mk XI | BMW | DP |
| 9 | Briscoe / Castroneves / Busch | Penske-Taylor Racing | Wayne Taylor/Roger Penske | Riley | Mk XI | Pontiac | DP |
| 10 | Taylor / Angelelli / Valiante / Taylor | SunTrust Racing | Wayne Taylor | Riley | Mk XI | Pontiac | DP |
| 11 | Duno / Primat / Mücke / Enge / Charouz / Dalziel | SAMAX | Peter Baron | Riley | Mk XI | Pontiac | DP |
| 12 | Schramm / Bell / Bell / Dallenbach / Kasemets | RVO Motorsports | Dave Watson | Riley | Mk XI | Pontiac | DP |
| 14 | Friedman / McGehee / Lazzaro / Kelleners | Autometrics Motorsports | Cory Friedman | Porsche | 997 GT3 Cup | Porsche | GT |
| 15 | Nastasi / Empringham / Dumoulin / Said | Blackforest Motorsports | Brian Nott | Ford | Mustang | Ford | GT |
| 16 | Bobbi / Garcia / Kimber-Smith | Cheever Racing (USA) | Eddie Cheever, Jr. | Fabcar | FDSC/03 | Pontiac | DP |
| 17 | Jensen / Jensen / Zitza / Taylor | Terra Firma Motorsports | Gary Jensen | Porsche | 997 GT3 Cup | Porsche | GT |
| 21 | Reindler / Alessi / Prewitt | Matt Connolly Motorsports | Matt Connolly | Pontiac | GTO.R | Pontiac | GT |
| 22 | de Quesada / Gabel / Woodman / Dumoulin / Scardina | Alegra Motorsports | Carlos de Quesada | Porsche | 997 GT3 Cup | Porsche | GT |
| 23 | Auberlen / Hand / Long / Wallace | Alex Job Racing | Alex Job | Crawford | DP03 | Porsche | DP |
| 26 | Jacalone / Jacalone / Schmidt | Gotham Competition | Jerome Jacalone | Porsche | 997 GT3 Cup | Porsche | GT |
| 29 | de Quesada / Basseng / Lieb / Gleason / Swartzbaugh | Alegra Motorsports | Carlos de Quesada | Porsche | 997 GT3 Cup | Porsche | GT |
| 30 | Dobson / Thorne / Michaelian / Michaelian | Racers Edge Motorsports | Jon Mirachi | Mazda | RX-8 | Mazda | GT |
| 34 | Willsley / Mowlem / Fitzgerald / Papadopoulos | Orbit | Rodger Hawley | Porsche | 997 GT3 Cup | Porsche | GT |
| 40 | Foster / Espenlaub / Dempsey | Hyper Sport | Joe Foster | Mazda | RX-8 | Mazda | GT |
| 42 | Sahlen / Nonnamaker / Nonnamaker / Nonnamaker | Team Sahlen | Mike Thomas | Chevrolet | Corvette | Chevrolet | GT |
| 43 | Sahlen / Nonnamaker / Nonnamaker / Nonnamaker | Team Sahlen | Mike Thomas | Chevrolet | Corvette | Chevrolet | GT |
| 44 | Paquette / Nixon | Bullet Racing | Steve Pacquette | Porsche | 996 GT3 Cup | Porsche | GT |
| 50 | Farano / Jensen / Cloud / Bradley | Blackforest Motorsports | Brian Nott | Ford | Mustang | Ford | GT |
| 51 | Newton / Erdos / Mayer | Cheever Racing | | Coyote | CC/08 | Pontiac | DP |
| 52 | Biagi / Pescatori / Bertuzzi / Monzón | Mastercar | | Ferrari | F430 | Ferrari | GT |
| 57 | Liddell / Davis / Pobst / Jeannette | Stevenson Motorsports | John Stevenson | Pontiac | GXP.R | Pontiac | GT |
| 58 | Donohue / Law / Rice | Brumos Porsche | Michael Colucci | Riley | Mk XI | Porsche | DP |
| 59 | France / Haywood / Barbosa / Borcheller | Brumos Porsche/Kendall (USA) | Michael Colucci | Riley | Mk XI | Porsche | DP |
| 60 | Patterson / Negri / Wilson / Rahal | Michael Shank Racing | Michael Shank | Riley | Mk XX | Ford | DP |
| 61 | Frisselle / Wilkins / Ranger / Braun | AIM Autosport | Ian Willis | Riley | Mk XX | Ford | DP |
| 62 | Ragginger / Baldwin / Burtin / Tucker / Zabinski | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 63 | Ende / Yarab, Jr. / Bourque / Maher | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 64 | Lowe / Pace / Van Overbeek / Sugden / Valentine | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 65 | Oasis / Atherton / Stout / Daskalos / Archer | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 66 | Miller / Collard / Ballou / Lally / Dumas | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 67 | Pumpelly / Sellers / Westbrook / George, Jr. | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 68 | Gomez / Auriemma / Mayes | TRG (USA) | Kevin Buckler | Porsche | 997 GT3 Cup | Porsche | GT |
| 69 | Assentato / Longhi / Segal / Pechnik | SpeedSource | Sylvain Tremblay | Mazda | RX-8 | Mazda | GT |
| 70 | Haskell / Tremblay / Ham / Matos | SpeedSource | Sylvain Tremblay | Mazda | RX-8 | Mazda | GT |
| 72 | Aschenbach / Lewis, Jr. / Stanton / Papis | Autohaus Motorsports | Nathan McBride | Pontiac | GXP.R | Pontiac | GT |
| 74 | Skea / Patch / Hamblin / Rosenzweig / Courtney | Autometrics Motorsports | Chris Mitchum | Porsche | 997 GT3 Cup | Porsche | GT |
| 75 | Krohn / van de Poele / Gavin | Krohn Racing | David Brown | Lola | B08/70 | Pontiac | DP |
| 76 | Jönsson / Zonta / Turner | Krohn Racing | David Brown | Lola | B08/70 | Pontiac | DP |
| 77 | Gidley / Jaeger / Gollin / Gardel | Doran Racing | Kevin Doran | Doran | JE4 | Ford | DP |
| 80 | Greenberg / Faulkner / Heylen / Arnold | Synergy Racing | Cole Scrogham | Porsche | 997 GT3 Cup | Porsche | GT |
| 81 | Johnson / Doornbos / Lietz / Huisman | Synergy Racing | | Porsche | 997 GT3 Cup | Porsche | GT |
| 83 | McCrackin / Smith / Walker | Farnbacher Loles Motorsports | | Porsche | 997 GT3 Cup | Porsche | GT |
| 84 | Bingham / Pickering / Cotter / Pennington / Kitch | Farnbacher Loles Motorsports | Gregory Loles | Porsche | 997 GT3 Cup | Porsche | GT |
| 85 | Kitch / Bentley / Miller / Pallis | Farnbacher Loles Motorsports | Gregory Loles | Porsche | 997 GT3 Cup | Porsche | GT |
| 86 | Henzler / Lux / Keen / Maassen / Bergmeister | Farnbacher Loles Motorsports | Gregory Loles | Porsche | 997 GT3 Cup | Porsche | GT |
| 87 | Werner / Farnbacher / Ehret / Bernhard | Farnbacher Loles Motorsports | Gregory Loles | Porsche | 997 GT3 Cup | Porsche | GT |
| 88 | Stippler / Kaffer / Lacey / Wilkins | Farnbacher Loles Motorsports | Gregory Loles | Porsche | 997 GT3 Cup | Porsche | GT |
| 89 | Drudi / Giammaria / Rosa / Hardt / Petrobelli | Farnbacher Loles Motorsports | | Porsche | 997 GT3 Cup | Porsche | GT |
| 90 | Thornton / Long / Varde / Russell | Automatic Racing | | BMW | M6 | BMW | GT |
| 91 | Matthews / Goossens / Hunter-Reay / O'Connell | Bob Stallings/Riley-Matthews | Bill Riley | Riley | Mk XX | Pontiac | DP |
| 99 | Johnson / Gurney / Fogarty / Vasser | Gainsco/Bob Stallings Racing | Bob Stallings | Riley | Mk XI | Pontiac | DP |