Industry Minister James Moore says most of Bill C-28 will be the law of the land as of July 1, 2014.
Experts say the delay in enacting the law was the result of intense lobbying by industry players, who tried to generate fear and uncertainty about its effects.
The law provides tough new penalties and sets out some aggressive standards for how companies can use people's personal information for marketing purposes.
Law professor Michael Geist advocated for an anti-spam law nearly a decade ago.
Geist, who holds the Canada Research Chair in Internet and E-commerce Law at the University of Ottawa, says the law is long overdue.
"It's rather incredible to think how long this process has taken," he said in an interview.
"Canada has lagged badly behind other countries when it comes to addressing some of these issues," he said.
The law allows companies to send business-related messages internally or to another business.
Emails sent as part of a product recall, in response to a consumer inquiry or as a result of a referral may also be allowed.
And the law won't change the way charities are currently allowed to reach out to potential donors.
But the law will ban the most deceptive forms of spam, such as identity theft, phishing and spyware, says Moore.
The Public Interest Advocacy Centre says the legislation will "mark a new era in consumers' and citizens' use of the Internet to communicate with businesses."
"Consumers and citizens will now be better able to decide for themselves whether and how they will engage with companies using electronic means for commercial messages," said the centre's executive director John Lawford.
The government estimates that Internet spam costs the Canadian economy more than $3 billion annually.
Australia, Britain and the United States have for years had strong laws on the books to combat online threats.
Canada's law faces a mandatory review in three years.
Under the legislation, consumers will control who can send them a commercial electronic message or business email.
Even after being given consent, companies will have to identify themselves in their messages and provide a way for consumers to unsubscribe from receiving further emails.
Companies failing to comply with the law will face financial penalties.
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