Attorney General Bill Lockyer brought the case against PW Marketing of Los Angeles County and its owners Paul Willis and Claudia Griffin in 2002 under a 1998 anti-spam law.
The stiff verdict, it is hoped, could help to deter spammers from clogging email accounts worldwide by sending out junk emails.
PW Marketing and Willis and Griffin were charged with sending out millions of emails advertising "how to" guides on spamming and long lists of email addresses.
The judgment, which Lockyer has said would be the model for future spam injunctions, forbids PW Marketing from sending unsolicited commercial email, accessing computers that belong to other people without their permission and disguising its identity by sending emails that appear to originate from a different address.
The injunction also forbids Willis and Griffin for 10 years from owning or managing any business that advertises on the internet.
Under newly amended Californian laws, individuals can sue spammers and collect damages up to $1000 an email.