Anyone found to have obtained the services of a prostitute could face a fine of up to£1,000.
They will also be named and shamed and have a criminal record as officials attempt to limit the sex trade on Scotland's streets.
Until the Prostitution (Public Places) (Scotland) Act 2007 was passed in February, only prostitutes had been committing a criminal act.
But now those who seek to pick up sex workers will also be guilty of an offence, while measures are in place to try to ensure offenders are also banned from driving.
Justice secretary Kenny MacAskill (SNP) said it showed that the authorities "will not turn a blind eye to the people who sustain and fuel this exploitative trade".
Pledge to do more
"It corrects an unfair legal position where only those engaged in prostitution could be targeted, while the kerb-crawlers demanding their services - often harassing the wider community in the process - get off scot-free," he said.
He acknowledged that making kerb-crawling illegal would not by itself solve the issue and pledged to work with councils, police and community planning partners.
"But while we rightly seek to help those individuals trapped in prostitution, we simply cannot, and will not sit back and let the demand that fuels this deeply damaging and dangerous trade go unchallenged," Mr MacAskill added.
Four Scottish cities where street prostitution is most problematic, Aberdeen, Dundee, Edinburgh and Glasgow, were in February given£1m in funding for 200708 to tackle the issue at a local level.
New powers at the disposal of police
Assistant chief constable John Neilson, who leads on prostitution for the Association of Chief Police Officers in Scotland, echoed Mr MacAskill's comments, saying the new act "changes fundamentally the power that our police officers can wield in tackling the purchaser".
"This is a welcome piece of legislation and an effective tool for us to use in areas where there is a known prostitution problem," Mr Neilson said.