In a statement, the rebel group says it is important that people can vote "in freedom," without specifying when the ceasefire is expected to begin.
The announcement comes at a time when there have been reports of increased violence and threats against politicians during the run-up to the election.
Examples include Senator Aida Quilcué, who was kidnapped earlier in February but released a few hours later, and presidential candidate Miguel Uribe, who was shot during a speech in the capital Bogotá this summer and later died.
Colombia's parliamentary elections will be held on March 8 and the presidential election is on May 31.
President Gustavo Petro suspended peace negotiations with the ELN last year in connection with a wave of violence and attacks in the northeastern parts of the country.
