Audience measurement by Nielsen Media Research, commonly referred to as Nielsen ratings, has provided World Series television ratings since at least 1963.^{[1][lower-alpha 1]} Key measurements are ratings, the percentage of all U.S. television-equipped households that watched a game, share, the percentage of television sets in use that were tuned to a game, and total viewers (or viewership), the average number of people watching a game throughout its duration.^[4]

The highest ratings for an entire World Series is tied between 1978, featuring the New York Yankees and Los Angeles Dodgers, and 1980, featuring the Philadelphia Phillies and Kansas City Royals. Both series went six games and averaged a rating of 32.8 and a share of 56.^[5] Average viewership was slightly larger in 1978 (44,278,950) than in 1980 (42,300,000).^[5]

The lowest ratings for an entire World Series was in 2023, a five-game series won by the Texas Rangers over the Arizona Diamondbacks, which averaged a 4.7 rating with a 14 share; it also had the lowest average viewership, at 9.082 million. Previously, the 2020 series in which the Los Angeles Dodgers defeated the Tampa Bay Rays in six games was the least watched, averaging a 5.2 rating and a 12 share.

The highest-rated individual game in World Series history was Game 6 in 1980, when the Philadelphia Phillies defeated the Kansas City Royals; the game had a 40.0 rating.^[5][6] The only other games with a rating of 39 or higher were Game 7 in 1975, when the Cincinnati Reds defeated the Boston Red Sox, with a 39.6 rating,^[5] and Game 4 in 1963, when the Los Angeles Dodgers swept the New York Yankees, with a 39.5 rating.^[6][1] The most-viewed game was Game 7 in 1986, when the New York Mets defeated the Boston Red Sox;^[7] with a rating of 38.9,^[5] its viewership is estimated at 55 to 60 million.^{[8][lower-alpha 2]}

The lowest-rated individual game was Game 2 in 2023, which had a 4.0 rating.^[9] Though the game did not have the smallest viewership in World Series history, that mark belongs to Game 3 in 2023 at 8.126 million. That game had a 4.2 rating.^[10] The previous least viewed game was Game 2 in 2023, which had 8.153 million viewers.^[9] Prior to 2020, the only World Series game with less than 10 million viewers had been Game 3 in 2008,^[11] which was impacted by a rain delay and had 9.836 million viewers.^[12]

The most recent World Series game to record a rating of 30 or higher was Game 7 in 1991, as the Minnesota Twins defeated the Atlanta Braves; the game had a viewership of 50.340 million.^[5] Game 7 in 2016 between the Chicago Cubs and Cleveland Indians had an average viewership of 40.045 million—the most-watched World Series game in 25 years dating back to 1991^[13]—and peaked at 49.9 million viewers, and Fox estimated more than 75 million people watched all or part of the game.^[14]

All four major U.S. broadcast television networks (ABC, CBS, NBC, and Fox) have broadcast the World Series. Fox has been the exclusive broadcast network for the World Series since 2000, and has a contract with MLB to carry the World Series through 2028.^[15]

The graph below shows the average rating (in percentage) and average number of viewers (in millions) for each World Series since 1973; older Nielsen records lack average viewer counts.^[5][16] For example, the 1973 World Series (the leftmost data points) had an average rating of 30.7 (percentage of all U.S. television-equipped households that watched) and an average viewership of 34.8 (million viewers). This chart shows trending over time; specific figures are available in the television ratings by year section.

Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org.

These tables list the World Series with the smallest and largest average viewership (figures in millions) since 1973.^[5][16][17]

The following table shows the viewership (figures in millions) records—both largest and smallest—for games one through seven in a World Series since 1973.^[5][16][18]

Figures are expressed as ratings/share. Ratings represent the percentage of U.S. households that watched the game on television. Share represents the percentage of television sets in use that were tuned to the game.

Source: 1968 through 2007 figures are per Nielsen documents;^[5][16] more recent years per inline citations.

• Super Bowl television ratings
• NBA Finals television ratings
• Stanley Cup Finals television ratings
• MLS Cup television ratings