Some of the Longest Running Television Comedies

By number of seasons: 

20  The Simpsons (Spring 2009)
14  (The Adventures Of) Ozzie And Harriet
13  King Of The Hill (Spring 2009), South Park (Spring 2009)
12  My Three Sons
11  M*A*S*H, Cheers, The Danny Thomas Show / Make Room For Daddy, Happy Days, The Jeffersons, Married ... With Children, Frasier
10  Murphy Brown, Mystery Science Theater 3000, Friends
9  The Beverly Hillbillies, The Love Boat, Alice, Roseanne, Family Matters, Coach, All In The Family, One Day At A Time, Night Court, The Drew Carey Show, Everybody Loves Raymond, The King Of Queens

By number of episodes: 
435 (The Adventures Of) Ozzie & Harriet 

430+ The Simpsons (Spring 2009)
380 My Three Sons
336 The Danny Thomas Show / Make Room For Daddy
275 The Donna Reed Show, Cheers

274 The Beverly Hillbillies

264 Frasier
259 Married ... With Children
256 M*A*S*H
255 Happy Days
253 The Jeffersons
252 Bewitched
249 The Andy Griffith Show
247 Murphy Brown

245 The Love Boat
244+ King Of The Hill (Spring 2009)

238 Friends
234 Leave It To Beaver

233 The Drew Carey Show
222 Roseanne
214 Family Matters
210 All In The Family
209 One Day At A Time, The Facts Of Life, Everybody Loves Raymond
207 The King Of Queens
204 Home Improvement
202 Alice
201 The Cosby Show
200 Coach

193 Night Court, Will & Grace