The 1991 DieHard 500 was the 17th stock car race of the 1991 NASCAR Winston Cup Series and the 23rd iteration of the event. The race was held on Sunday, July 28, 1991, before an audience of 95,000 in Lincoln, Alabama at Talladega Superspeedway, a 2.66 miles (4.28 km) permanent triangle-shaped superspeedway. The race took the scheduled 188 laps to complete. In the final laps of the race, Richard Childress Racing driver Dale Earnhardt would manage to fend off the field, leading the final 28 laps of the race to take his 51st career NASCAR Winston Cup Series victory and his third victory of the season.^[1][2][3][4] To fill out the top three, Melling Racing driver Bill Elliott and Roush Racing driver Mark Martin would finish second and third, respectively.

Talladega Superspeedway, originally known as Alabama International Motor Superspeedway (AIMS), is a motorsports complex located north of Talladega, Alabama. It is located on the former Anniston Air Force Base in the small city of Lincoln. The track is a tri-oval and was constructed in the 1960s by the International Speedway Corporation, a business controlled by the France family. Talladega is most known for its steep banking and the unique location of the start/finish line that's located just past the exit to pit road. The track currently hosts the NASCAR series such as the NASCAR Cup Series, Xfinity Series and the Camping World Truck Series. Talladega is the longest NASCAR oval, a 2.66-mile-long (4.28 km) tri-oval like the Daytona International Speedway, which also is a 2.5-mile-long (4.0 km) tri-oval.

Qualifying was split into two rounds. The first round was held on Thursday, July 24, at 4:30 PM EST. Each driver would have one lap to set a time. During the first round, the top 15 drivers in the round would be guaranteed a starting spot in the race. If a driver was not able to guarantee a spot in the first round, they had the option to scrub their time from the first round and try and run a faster lap time in a second round qualifying run, held on Friday, July 25, at 4:30 PM EST. As with the first round, each driver would have one lap to set a time. For this specific race, positions 16-40 would be decided on time,^[5] and depending on who needed it, a select amount of positions were given to cars who had not otherwise qualified but were high enough in owner's points; up to two provisionals were given. If needed, a past champion who did not qualify on either time or provisionals could use a champion's provisional, adding one more spot to the field.

Sterling Marlin, driving for Junior Johnson & Associates, would win the pole, setting a time of 49.853 and an average speed of 192.085 miles per hour (309.131 km/h) in the first round.^[6][7]

Two drivers would fail to qualify.