Which fighter holds the record for winning a world title after the least fights?

[Phil]

Depends what you mean by world title:

Samson Dutch Boy Gym won a world title in 4 fights

http://www.boxrec.com/boxer_display.php?boxer_id=008222

nice old record he's got! was he any use?

The victories over Pascau, Soto and Carbajal (Cruz), showed he had real potential.

But he never met an absolute top notch opponent to show how good he really was.

pity guys like this this don't meet the best, cc for the info!