| 10.1.1999 | Daytona Test | 3 | Mk III | Whittington / Whittington / Haywood | DLW Racing Inc. | 10th |
| 10.1.1999 | Daytona Test | 8 | Mk III | Schubot / Camferdam | Transatlantic Racing | 5th |
| 10.1.1999 | Daytona Test | 16 | Mk III | Leitzinger / Wallace / Hayner / Weaver | Dyson Racing Team, Inc. | 2nd |
| 10.1.1999 | Daytona Test | 20 | Mk III | Dyson / Weaver / Forbes-Robinson / Schroeder / Hayner | Dyson Racing Team, Inc. | 3rd |
| 10.1.1999 | Daytona Test | 29 | Mk III | Brown / Mirro | Intersport Wheel Works | 14th |
| 10.1.1999 | Daytona Test | 74 | Mk III | Robinson / Baldwin / Hoerr / Gooding | Robinson Racing | 9th |
| 10.1.1999 | Daytona Test | 95 | Mk III | Volk / Schroeder / Debban / St. James / Valentine | TRV Motorsport | 15th |
| 31.1.1999 | 24 h Daytona | 3 | Mk III | Haywood / Whittington / Whittington / Sullivan | DLW Racing Inc. | 23rd |
| 31.1.1999 | 24 h Daytona | 5 | Mk III | Haywood / Sullivan / Whittington / Whittington | DLW Racing Inc. | DNA |
| 31.1.1999 | 24 h Daytona | 8 | Mk III | Salazar / Dayton / Camferdam / Schubot | Transatlantic Racing | 5th |
| 31.1.1999 | 24 h Daytona | 15 | Mk III | Bentley / Bingham / André / Fréon | Hybrid Racing | 47th |
| 31.1.1999 | 24 h Daytona | 16 | Mk III | Weaver / Dyson / Schroeder / Hayner | Dyson Racing Team, Inc. | 22nd |
| 31.1.1999 | 24 h Daytona | 20 | Mk III | Leitzinger / Wallace / Forbes-Robinson | Dyson Racing Team, Inc. | 1st |
| 31.1.1999 | 24 h Daytona | 29 | Mk III | Brown / Brickell / Mucha / Mirro | Intersport Wheel Works | 63rd |
| 31.1.1999 | 24 h Daytona | 30 | Mk III | Mucha / Brown / Dromm / Valentine / Brickell | Intersport Wheel Works | DNA |
| 31.1.1999 | 24 h Daytona | 74 | Mk III | Robinson / Baldwin / Hoerr / Gooding | Robinson Racing | 55th |
| 31.1.1999 | 24 h Daytona | 95 | Mk III | Schroeder / Volk / Debban / Valentine | TRV Motorsport | 21st |
| 20.3.1999 | 12 h Sebring | 0 | Mk III | van de Poele / Saelens / Enge | Team Rafanelli SRL | 37th |
| 20.3.1999 | 12 h Sebring | 5 | Mk III | Whittington / Haywood / Whittington | Whittington Brothers, Inc. | 42nd |
| 20.3.1999 | 12 h Sebring | 8 | Mk III | Schubot / Camferdam / Dayton | Transatlantic Racing | 17th |
| 20.3.1999 | 12 h Sebring | 15 | Mk III | Bentley / Bingham / Duez | Hybrid R&D | 7th |
| 20.3.1999 | 12 h Sebring | 16 | Mk III | Weaver / Wallace / Schroeder | Dyson Racing | 29th |
| 20.3.1999 | 12 h Sebring | 20 | Mk III | Leitzinger / Forbes-Robinson / Weaver | Dyson Racing | 2nd |
| 20.3.1999 | 12 h Sebring | 29 | Mk III | Mirro / Brown / Brickell / Petery | Intersport Racing | 32nd |
| 20.3.1999 | 12 h Sebring | 31 | Mk III | Fairbanks / Dullum / Baumann | Genesis Racing | 21st |
| 20.3.1999 | 12 h Sebring | 44 | Mk III Series 2 / Autoexe LMP99 | Fréon / Terada | Autoexe Motorsports | 35th |
| 20.3.1999 | 12 h Sebring | 74 | Mk III | Baldwin / Robinson / Hoerr | Robinson Racing | 25th |
| 20.3.1999 | 12 h Sebring | 95 | Mk III | Schroeder / Halsmer | TRV Motorsport | 48th |
| 28.3.1999 | 2 h 30 min Barcelona | 16 | Mk III | Gabbiani / Ortiz | Conrero | DNA |
| 28.3.1999 | 2 h 30 min Barcelona | 25 | Mk III | Riccitelli / Blieninger | RWS Motorsport | DNF |
| 28.3.1999 | 2 h 30 min Barcelona | 31 | Mk III | Gache / Formato | Riley & Scott Europe | DNF |
| 11.4.1999 | 500 km Monza | 15 | Mk III Series 2 | Caffi / de Lorenzi | Target 24 | DNF |
| 11.4.1999 | 500 km Monza | 16 | Mk III | Gabbiani / Gabellini / Corradi | Conrero | DNF |
| 11.4.1999 | 500 km Monza | 25 | Mk III | Riccitelli / Blieninger | RWS Motorsport | DNF |