These are the most famous mob fugitives that i can think of right now that were on the run(or still are)for the longest time...

Matteo Messina Denaro is on the run since 1993

Bernardo Provenzano has been on the run from police for more than four decades

Whitey Bulger was 16 years in hiding

Lo Piccolo had been a fugitive since 1983 until 2007

Giuseppe Falsone had been on the run for 10 years

Gerlandino Messina had been on the run for 11 years

Domenico Raccuglia has been on the run for 15 years

From the old timers Vito Genovese was on the run in Italy for 7 or 8 years i think

And i gotta put Casso at the end,although he was only 3 years as a fugitive he had a lot of "operations" goin on at the time while he was on the run

any other thoughts to be added to the list?