The measure extends “the emergency regime… (to continue) the reestablishment of order, citizen security and territorial control,” and was passed by 67 votes in favor in the 84-seat unicameral Congress.
It was the 10th extension of the state of emergency and will come into force from January 17 to February 15 to tackle gangs that Bukele says control around 80 percent of the country.
It was first introduced in late March, after a wave of murders attributed to criminal gangs that have plagued El Salvador and other countries in the region.
The state of emergency has been criticized by human rights groups, with particular concern expressed about the powers it grants authorities to make arrests without warrants.
Suecy Callejas, vice-president of the assembly, said the measures were needed to “save the lives of Salvadorans”.
According to official statistics, more than 61,000 alleged gang members have been arrested under the state of emergency, including 900 leaders, mostly from Mara Salvatrucha (MS-13) and Barrio 18