Most Losses by a Team in a Season (MLB)

The 1899 Cleveland Spiders hold the MLB team record for losses in a season, with 134. Next best is the 2024 Chicago White Sox, at 121.

#	Team	Season	G	L
1	Cleveland Spiders	1899	154	134
2	Chicago White Sox	2024	162	121
3	New York Mets	1962	161	120
4	Detroit Tigers	2003	162	119
4	Colorado Rockies	2025	162	119
6	Philadelphia Athletics	1916	154	117
7	Boston Braves	1935	153	115
7	Baltimore Orioles	2018	162	115
9	Detroit Tigers	2019	161	114
10	Pittsburg Alleghenys	1890	138	113
10	Washington Senators	1904	157	113
12	Pittsburgh Pirates	1952	155	112
12	New York Mets	1965	164	112
12	Oakland Athletics	2023	162	112
15	Louisville Colonels	1889	140	111
15	St. Louis Browns	1898	154	111
15	Boston Red Sox	1932	154	111
15	St. Louis Browns	1939	156	111
15	Philadelphia Phillies	1941	155	111
15	New York Mets	1963	162	111
15	Arizona Diamondbacks	2004	162	111
15	Houston Astros	2013	162	111
23	Washington Senators	1909	156	110
23	San Diego Padres	1969	162	110
23	Montreal Expos	1969	162	110
23	Arizona Diamondbacks	2021	162	110
23	Baltimore Orioles	2021	162	110
28	Philadelphia Athletics	1915	154	109
28	Philadelphia Phillies	1928	152	109
28	Philadelphia Phillies	1942	151	109
28	New York Mets	1964	163	109
28	Toronto Blue Jays	1979	162	109
28	Detroit Tigers	1996	162	109
34	Boston Doves	1909	155	108
34	St. Louis Browns	1937	156	108
34	Philadelphia Phillies	1945	154	108
34	Oakland Athletics	1979	162	108
34	Florida Marlins	1998	162	108
34	Baltimore Orioles	2019	162	108
40	St. Louis Browns	1910	158	107
40	Boston Rustlers	1911	156	107
40	St. Louis Browns	1911	152	107
40	Baltimore Terrapins	1915	154	107
40	Boston Red Sox	1926	154	107
40	Philadelphia Phillies	1961	155	107
40	Montreal Expos	1976	162	107
40	Toronto Blue Jays	1977	161	107
40	Baltimore Orioles	1988	161	107
40	Houston Astros	2012	162	107
40	Washington Nationals	2022	162	107
51	Philadelphia Athletics	1920	156	106
51	Philadelphia Phillies	1939	152	106
51	Washington Senators	1963	162	106
51	Chicago White Sox	1970	162	106
51	Atlanta Braves	1988	160	106
51	Detroit Tigers	2002	161	106
51	Milwaukee Brewers	2002	162	106
51	Tampa Bay Devil Rays	2002	161	106
51	Kansas City Royals	2005	162	106
51	Houston Astros	2011	162	106
51	Kansas City Royals	2023	162	106
62	Boston Americans	1906	155	105
62	St. Louis Cardinals	1908	154	105
62	Boston Red Sox	1925	152	105
62	Philadelphia Phillies	1938	151	105
62	Philadelphia Athletics	1943	155	105
62	Philadelphia Athletics	1946	155	105
62	Kansas City Athletics	1964	163	105
62	Texas Rangers	1973	162	105
62	Cleveland Indians	1991	162	105
62	Pittsburgh Pirates	2010	162	105
62	Miami Marlins	2019	162	105
73	Brooklyn Superbas	1905	155	104
73	Philadelphia Athletics	1919	140	104
73	Philadelphia Phillies	1923	155	104
73	Washington Senators	1949	154	104
73	Detroit Tigers	1952	156	104
73	Pittsburgh Pirates	1953	154	104
73	Seattle Mariners	1978	160	104
73	Pittsburgh Pirates	1985	161	104
73	Kansas City Royals	2004	162	104
73	Kansas City Royals	2018	162	104
73	Colorado Rockies	2026	162	104
84	Boston Beaneaters	1905	156	103
84	New York Highlanders	1908	155	103
84	Pittsburgh Pirates	1917	157	103
84	Philadelphia Phillies	1921	154	103
84	Boston Red Sox	1927	154	103
84	Philadelphia Phillies	1927	155	103
84	Boston Braves	1928	153	103
84	Philadelphia Phillies	1940	153	103
84	Philadelphia Athletics	1954	156	103
84	Chicago Cubs	1962	162	103
84	Kansas City Athletics	1965	162	103
84	Chicago Cubs	1966	162	103
84	Seattle Mariners	1980	163	103
84	Detroit Tigers	1989	162	103
84	New York Mets	1993	162	103
84	Washington Nationals	2009	162	103
84	Minnesota Twins	2016	162	103

A team's total is its players' numbers for the club added up, so a player traded mid-season counts for each team only what he did there. Rates such as ERA and batting average are worked out from the team's summed totals, not averaged across players.