In Major League Baseball, the trend throughout the 1960s was of increased pitching dominance. After the record home run year by Roger Maris in 1961, the major leagues increased the size of the strike zone from the top of the batter's shoulders to the bottom of his knees. A significant "power shortage" culminated in 1968, with far fewer runs scored than in the early 1960s.
Hitting was anemic as Carl Yastrzemski of the Boston Red Sox would be the only American League hitter to finish the season with a batting average higher than .300. Yastrzemski's batting average of .301 was the lowest batting average of any league batting champion. The American League's collective slugging average of .340 remains the lowest since 1915 (when the game was still in the so-called dead-ball era), while the collective batting average of .231 is the all-time lowest. As a result of the dropping offensive statistics, Major League Baseball Rules Committee took steps to reduce the advantage held by pitchers by lowering the height of the pitchers mound from 15 inches to 10 inches, and by reducing the size of the strike zone for the 1969 season. 1969 batting averages climbed back to their historical averages and never again would pitching have as large a statistical average over batting in the major leagues.
1968 was the final year when baseball had no divisions within the two leagues, with the only post-season competition being the World Series itself. Four expansion teams would join baseball for the season following in 1969. This was also the first season that the Athletics franchise played in Oakland, California, after their departure from Kansas City, Missouri.
February 6 – Voters in King County, Washington, approve by 62 percent a $40 million bond issue to build a domed, multipurpose stadium. The Kingdome, being built between 1972 and 1976, would operate from 1976 until its demolition in 2000.
February 13 – The San Francisco Giants and Los Angeles Dodgers execute a four-player trade, with Tom Haller one of the two players going to Los Angeles and Ron Hunt one of the two going to San Francisco. The trade is the first between the two clubs since their move to the West Coast, and also the first since the one that would have sent Jackie Robinson from the Brooklyn Dodgers to the New York Giants after the 1956 season, but he retired rather than report with his new team.
April 15 – At the Astrodome, the Houston Astros defeat the New York Mets 1–0 in a 24-inning, 6-hour, 6-minute marathon. In the bottom of the 24th, Bob Aspromonte's bases-loaded ground ball goes through the legs of Met shortstop Al Weis for an error (the only one committed by the Mets all game) that plates Norm Miller for the winning run. To date, the game is the longest to end in a shutout in terms of both innings and duration.
April 19 – Nolan Ryan of the New York Mets becomes the sixth pitcher in National League history to strike out the side on nine pitches. But Los Angeles wins 3–2 at New York's Shea Stadium.
September 14 – Denny McLain becomes the first 30-game winner since Dizzy Dean in 1934 as the Detroit Tigers beat the Oakland Athletics, 5–4, at Detroit's Tiger Stadium. Reggie Jackson's home run in the 4th puts the A's ahead 2–0, but Norm Cash answers with a three-run shot. Jackson hits another in the 6th, but the Tigers push across two in the 9th to win. Al Kaline, pinch hitting for McLain, walks and scores the tying run. McLain, who posted a 31–6 record in the regular season, gives up six hits and strikes out 10.
September 18 – Sixteen hours after Perry's feat, Ray Washburn of the St. Louis Cardinals makes major league history by hurling a second consecutive no-hitter in the same park. Run-scoring hits by Mike Shannon and Curt Flood at Candlestick down the Giants, 2–0. This is the first time in history back-to-back no hitters have been pitched between the same two teams on two consecutive days.
September 22 – Minnesota Twinsutility playerCésar Tovar plays all nine positions, an inning each, against the Oakland Athletics. Duplicating the feat that Bert Campaneris performed three years earlier, Tovar tops Campy by starting as pitcher and allows no hits or runs, for a 0.00 earned run average. In the inning, the first man to face Tovar was Campaneris, who fouls out. Tovar then strikes out slugger Reggie Jackson. Tovar is charged with a walk and a balk in the scoreless inning; his other contributions to the 2-1 Minnesota win include a single, a walk, a stolen base and a run scored. He makes five putouts and an assist, with no fielding errors.
September 28 – Mickey Mantle plays in his 2,401st and final game, eight days after hitting his last home run ending his career with 536.
Carl Yastrzemski of the Boston Red Sox goes 0-for-5 but maintains a .3005 batting average, to win his second straight American League batting crown with the lowest winning average ever. Yastrzemski is the league's only .300 hitter. Danny Cater of the Oakland Athletics ends second with a .290 average.
October 10 – In Game Seven of the World Series, Mickey Lolich of the Detroit Tigers, pitching on two days rest, wins his third game of the Series as he beats Bob Gibson and the St. Louis Cardinals, 4–1. Lolich brings Detroit its first World Championship since 1945. Lolich hurls a five-hitter, and is named Series MVP. Key moments came in the 6th inning when Lolich picks Lou Brock and Curt Flood off first base to keep the score 0–0. With the game scoreless in the 7th, the Tigers have two on and two out when Jim Northrup hits a line drive to center field. Gold-glover Flood misjudges the ball and starts in, allowing the ball to sail over his head for a triple. Northrup then scores on Bill Freehan's double for a 3–0 lead. Each team adds a 9th inning run to account for the 4–1 final score. It is the first time the Cardinals have ever lost a 7th game of a World Series. The Tigers become only the 3rd team to rally from a 3–1 deficit to win the Series 4 games to 3 (the 1925 Pirates and 1958 Yankees are the first two). The Tigers become the last team to win the championship between two first-place teams from leagues without division play where the pennant is automatically awarded to the team with the best won-lost record in its league.
January 26 – Eddie Phillips, 66, catcher for the Boston Braves, Detroit Tigers, Pittsburgh Pirates, New York Yankees, Washington Senators, and Cleveland Indians between 1924 and 1935
February 7 – Ollie Marquardt, 65, second baseman for the 1931 Boston Red Sox; later a successfully minor league manager
February 11 – Dorothea Downs, (?), All-American Girls Professional Baseball League player
February 26 – Rip Collins, 72, a four-sport star at Texas A&M University, who pitched in the American League for the New Yankees, Boston Red Sox, Detroit Tigers and St. Louis Browns from 1920 to 1931, and also was a member of the 1921 AL champion Yankees team
February 29 – Lena Blackburne, 81, infielder, manager and coach in almost a 30-year baseball career, who also originated the idea of rubing mud on new baseballs to remove their slippery finish
March 30 – Bernie Hungling, 72, catcher for the Brooklyn Robins and St. Louis Browns between 1922 and 1930
April 19 – Tommy Bridges, 61, 6-time All-Star pitcher who won 194 games for the Detroit Tigers, including three 20-win seasons and a 4–1 World Series record
April 26 – John Kroner, 57, second baseman for the Boston Red Sox and Cleveland Indians in the 1930s
April 29 – Terris McDuffie, 57, Negro League pitcher in a long career that spanned from 1930 through 1954, playing for several teams in different leagues across the United States, Canada and Latin America
May 5 - Chippy Gaw, 76, pitcher for the 1920 Chicago Cubs
May 26 – Doc Ayers, 78, spitball pitcher for the Washington Senators and Detroit Tigers
June 11 – Dan Boone, 73, a pitcher for the Philadelphia Athletics, Detroit Tigers and Cleveland Indians from 1920 through 1923
June 11 – Bill Regan, 69, second baseman for the Boston Red Sox, who became the first player in the team's history to hit two home runs in the same inning (1928), a mark only matched by Ellis Burks 62 years later
June 15 – Sam Crawford, 88, Hall of Fame right fielder for the Tigers, a lifetime .309 hitter who hit a record 312 triples, led both leagues in home runs, and retired with the 5th-most RBI in history