The 54-year-old, who was capped 86 times between 1979 and 1988, revealed he has been fighting the problems for several years.
"I am in a bad way. Arsenal are trying to help me, but I have got to try to help myself," Sansom told The Sun.
"I have been living homeless for 10 days, that's because I've got no money, I'm a drunk, I'm not feeling very well and I'm a gambler.
"I've been living on the street."
The defender spent eight years at the Gunners, who confirmed they are doing all they can to aid his recovery.
"We are aware of Kenny Sansom's situation and have been providing him with ongoing support and guidance," a club statement read.