Giants
Through the 2008 season, both the Dodgers and Giants have lost 12 World Series.
Mets
the Yankees
As of the 2008 season, the New York Yankees have lost the most World Series with 13. They have also won the most World Series at 26.
The San Diego Padres lost the 1984 World Series to the Detroit Tigers 4 games to 1.
MoNkEyS
It has never happened in World Series history.
Won 2 World Series. 1920 and 1948. Lost 3 World Series 1054, 1995 and 1997.
The Texas Rangers lost the 2010 World Series in five games to the San Francisco Giants. A year later, they lost the 2011 World Series in seven games to the St. Louis Cardinals.
The Chicago Cubs have reached the Postseason 15 times as of 20091. 1907 - Won World Series (DET 4-0)2. 1908 - Won World Series (DET 4-1)3. 1910 - Lost World Series (PHA 1-4)4. 1918 - Lost World Series (BOS 2-4)5. 1929 - Lost World Series (PHA 1-4)6. 1932 - Lost World Series (NYY 0-4)7. 1935 - Lost World Series (DET 2-4)8. 1938 - Lost World Series (NYY 0-4)9. 1945 - Lost World Series (DET 3-4)10. 1984 - Lost NLCS (SD 2-3)11. 1989 - Lost NLCS (SF 1-4)12. 1998 - Lost NLDS (ATL 0-3)13. 2003 - Lost NLCS (FLA 3-4)14. 2007 - Lost NLDS (ARI 0-3)15. 2008 - Lost NLDS (LAD 0-3)
Zero. The Texas Rangers have never won a World Series.
They have played in 40 World Series and have won 27. So they have lost 13.