The joint announcement came after two years of sporadic attempts at communication between the two groups, and comes days after the ELN rejected a cease-fire during presidential elections, later this week, in which Santos is seeking re-election.
The six-point framework for the talks includes construction of "a stable and durable peace for Colombia," rights of victims, and an acknowledgement of the work of other countries "in assisting the two parties towards reaching this point."
The statement does not mention a timeline or location for the discussions.
The Santos government has been involved in peace talks with the Revolutionary Armed Forces of Colombia, a larger rebel group, since 2012.
The Colombia government has been battling the two rebel armies for the past 50 years.