All legislators will need to be tested twice every four-year term and any positive results will be made public, in an effort to raise transparency standards in parliamentary work.
Chilean legislators will begin random drug testing in the next few days after a proposal making it compulsory was approved last month, despite criticism from some lawmakers.
The first 78 Chilean deputies to be tested were randomly drawn this week, and will now have their first series of drug tests, in an effort to raise the standards of transparency in parliamentary work.
The new proposal states that all legislators will need to be tested twice every four-year term, and any positive results will be made public.
"There is nothing more important than giving people transparency, that their parliamentarians are not consumers," right-wing Deputy Juan Antonio Coloma told the country's public TV channel on Thursday.
It comes as the Finish prime minister said she would do a voluntary drug test after being filmed on a night out.
The Chilean proposal, however, has divided lawmakers along party lines in a country that is in the process of voting on a new constitution, looking to overhaul national politics.
"I do not agree with the procedure," independent legislator Marcela Riquelme told TV Nacional de Chile, with others calling the measure an "unacceptable show".
Legislators who refuse to take tests could be referred to the House Ethics Committee.