Starting Tuesday, police officers will have the right to demand a breath sample from any driver they lawfully stop.
The previous legislation required reasonable suspicion a person has been drinking.
Passed in June, the new law also bumps up the maximum penalties for many alcohol-impaired driving offences from five years to 10.
According to federal statistics, an average of almost four people die in Canada daily due to impaired driving.
The new law is intended to curb injuries and deaths related to drunk driving.
Mandatory alcohol screening is currently in place in more than 40 countries, including Australia, France, Germany, Ireland and Sweden.
— With files from The Canadian Press