The Rolex Cosmograph Daytona is a mechanical chronograph wristwatch designed to meet the needs of racing drivers by measuring elapsed time and calculating average speed. Its name refers to Daytona, Florida, where Formula 1 racing flourished in the early 20th century. It has been manufactured by Rolex since 1963 in three distinct generations (or series); the second series was introduced in 1988, and the third in 2000. While cosmetically similar, the second series introduced a self-winding movement (the first series is hand-wound), and with the third series Rolex brought the manufacturing of the movement in-house.

The first series included an "exotic" variant dial now known as the Rolex "Paul Newman" Daytona, named after the famous actor, who received the watch as a gift from his wife, Joanne Woodward, and popularized it by wearing it constantly while pursuing his racing career. Years later, the actor's watch, which he gifted to his daughter's boyfriend in 1984, was sold at auction in 2017 for a record (for wristwatches) $17.8 million. (As of December 2019, the most expensive watch ever sold at auction is the Patek Philippe Grandmaster Chime wristwatch (Ref. 6300A-010), fetching US$31.19 million (31,000,000 CHF) in Geneva on 9 November 2019).

The current Cosmograph Daytona is equipped with a tachymetric scale, a sweep seconds hand for reading to 1/8 of a second, and elapsed-time hours and minute displays. What’s unique about the Rolex calibre 4130 is the use of a vertical (rather than lateral) clutch to activate the chronograph. It was engineered to feature a reduced number of components for greater reliability. With a 40mm case, it is available in a variety of materials.

Rolex released three series of the Cosmograph Daytona. Prior to the release of the "Daytona", Rolex produced chronographs using movements sourced from outside manufacturers. They were housed in conventional and, starting in the 1940s, Oyster cases. Rolex introduced a more modern chronograph in 1955 (Ref 6234) and manufactured approximately 500 per year until 1961, the year it was discontinued. The dial of Reference 6234 was not marked "Cosmograph" or "Daytona". The reference (model) number is marked on the side of the case at the 12 o'clock position, where it is hidden under the strap lugs. The 6234 model has three smaller sub-dials, to mark the passage of seconds up to 60 seconds (at the 9 o'clock position), minutes up to 30 minutes (at the 3 o'clock position), and hours up to 12 hours (at the 6 o'clock position); all of these match the color of the main dial. It also featured a tachymeter scale on the outer chapter ring, and a telemeter scale on the inner chapter ring. Reference 6234 was succeeded by Reference 6238, which dropped the telemeter scale and updated its appearance to include many features that would be adopted by its successor 6239.

Rolex became the official timekeeper of the Daytona International Speedway in 1962, and to mark the occasion, Reference 6234 was replaced by Cosmograph Reference 6239, introduced in 1963 as the first chronograph from Rolex nicknamed "Daytona". However, the original Reference 6239 did not include "Daytona" on the dial (and was in fact nicknamed "Le Mans" for the famous 24 Hours Le Mans race). In addition to the chronograph details, the wristwatch featured a bezel engraved with a tachymeter, as the watch was intended for racing drivers.