This is a comprehensive list as best as I can tell. I didn't put this list together but it seems to check out for the most part. I found this on Sherdog, posted by "Buff" and the link is here.
With Tito Ortiz's recent sentencing and the expectations that fighters be perfect professionals at all times, I thought it interesting to see the number and names of professional MMA fighters arrested. The most interesting and disappointing part is the wide variety of crimes committed. From DUI's to armed robbery and everything in between, here is the list:
Jeremy Jackson - In Jail For Rape.
25 years. Very strange court case.
Joe Son - In jail for 450 years for gang rape. Arrested in 2008 for vandalism, DNA linked him back to some 1990 nastiness.
Hermes Franca - Sexual assault on a minor. In jail now.
Charles "Kid Khaos" Bennett - made a plea for legal money recently. Is constantly popping in and out for drugs, assaults, and more. Due for release in 2015, apparently.
War Machine - went crazy at a porno pool party and "bodies started hitting the floor", he got 2 years.
Aleks Emilienko - Armed robbery in Russia saw him get 4 years and a shitload of gangster prison tattoos (and hep c).
Vyal(I forget) Datsik -robbed a mobile phone shop in Russia, escaped to Norway, became a neo-nazi and got re-arrested.
Bas Rutten - went to jail in holland for beating up a load of bouncers and an undercover cop. Apparently had fun in jail.
Chris Leben - Think it was a DUI. He choked a guy out in jail for a demo and freaked out when he didnt wake up straight away.
Jimi Manuwa - Burglary and assault. Turned his life around and became a UK mma legend.
Lee Murray - Robbery. Britains biggest ever. 20 years in a Moroccan hell hole.
Paul Kelly - Herion ring leader. 13 years. Sentenced a couple of months ago.
Ryan Gracie - Found dead in a police sale after being arrested for a drugged up rampage in Brazil including carjacking, assault, theft, and DUI. His doctor fed him pills which reacted badly with the drugs he'd taken and his kidneys failed.
Rob Emerson - Assault. Was part of the "Lords of South County" rich kids that made a load of vids of them beating up lone individuals. Not sure he did time though.
Melvin Costa - Assault, robbery, and general assholeness... He has a large swastika tattooed on his chest. Interestingly he is also the first openly gay male MMA fighter I can think of. Edit -- think I'm mistaken on the gay thing, although he was in jail for a long time...
Mike Whitehead - Sexual assault on two girls. He had a load of weed plants out back and is doing a long stretch.
Josh Rosenthal - Weed cultivation and production. "Heisenthal" will be out in 3 years.
Tito Ortiz - Assault and battery (on Jenna). Did 29 days and a shitload of community service.
Frank Shamrock - Robbery, assault with a deadly weapon (a bat). Not much more is known, but the guy went to a federal prison for that one.
Matt Brown - Drug possession, assault, burglary... "The Immortal" got his name after an overdose in jail during one of a few stints he did. Turned his life completely around and is now a cult favourite fighter.
Jon Jones - DUI. Didnt do more than a night. Broken Bentley.
Quinton Jackson - The famous DUI hit-and-run police chase with miscarriage of pregnant lady in a truck with his picture on it. Dana got him out of jail. Can't believe I left this out.
Chael Sonnen -Fraud over some work on some buildings he owned that plumbers were supposed to work on but he just kept the cash. Gangster. Didnt do jail, but fucked his political career... Their loss though...
Reza Madadi - Armed robbery. Is free at the moment, trial impending. The CCTV pic I saw does look a lot like him...
Ryan Ford - him and another guy went to jail for home invasion, they were debt collectors, and in the process of 'debt collecting' Ford almost cut the victim's fingers off of his hand. (From 5 rounder).
Patrick Smith - Sexual Assault on a child in 1999. Failure to register as a sex offender in 2004.
Melvin Guillard - drug possesion and parole violation (for possession again).
Jeff "The Snowman" Monson - Some kind of assault and battery on one of his (many) girlfriends... I'm shady on the details, but I think it was more than one occasion... Whatever the details, he did 3 months.
Brandon Sailing - Felony rape of a minor. Domestic battery four years later... Has "88" tattoo meaning "Heil Hitler". Lied to get on Tate vs Rousey Strikeforce card... Class act, no doubt.
Kimo Leopoldo - Arrested for suspected possession of meth, turned out to be weed. Rumoured dead shortly after but is alive and well, beating Tank recently.
Jason "Mayhem" Miller - Burglary, breaking and entering (of a church, naked) and other tomfoolery. Did not do any jail time.
James "Just Bleed Guy" Ladner - Receiving stolen property (a tractor). Was released in 2012, whereabouts now unknown!
Arianny Celeste - Battery on her dickhead sounding boyfriend. Was late for the UFC event she was supposed to be carding that night, but ultimately she was never gonna be in that much trouble.