Turkey imposes weekend curfews to fight virus
The latest wave of restrictions also includes the closure of all cinemas and restricted hours for most stores and shopping malls.
Elementary schools will switch to remote learning until the end of the year.
"We are facing a serious situation," Erdogan told the nation after chairing a cabinet meeting at which the new measures were discussed.
"The number of cases and deaths have reached a serious level, starting with Istanbul, so we need to be more careful."
Erdogan said the curfew would apply from 8pm until 10am and start this weekend.
The nation of 83 million people on Tuesday reported 103 new Covid-19 deaths - the first time the daily toll topped 100 since April 25.
Turkey's 11,704 total deaths are relatively low when compared to nations with similar populations and the World Health Organisation has commended Ankara for its response.
It has required people to wear masks on the streets across big cities since July and applied the measure nationally in September.
But the WHO has rapped Turkey for being vague about how it counts new infections.
Turkey now publishes the number of coronavirus "patients".
Health Minister Fahrettin said in September that the figure only referred to people with symptoms - not everyone who tests positive for the virus.
The ministry now officially counts more than 420,000 "patients" but the total number of infections is unknown.
Erdogan said the restrictions could become tougher if the current trends continue.
But he stressed that he would prefer to avoid that in order to "keep our economy alive".
"If the curve of the epidemic continues its upwards course, discussing more painful measures will become unavoidable," he said.