It is a case that highlights growing concerns about press freedom in the country.
Wa Lone and Kyaw Soe Oo were arrested December 12 for allegedly acquiring "important secret papers" from two police officers.
The officers had worked in Rakhine state, where abuses widely blamed on Myanmar's military have driven hundreds of thousands of Rohingya Muslims to flee into neighbouring Bangladesh.
The charges against the two are punishable by up to 14 years in prison.
Rights and media groups have criticised Myanmar's civilian government for continuing to use colonial-era laws to threaten and imprison journalists.
Meanwhile former US president Bill Clinton called for the immediate release of the journalists.
"A free press is critical to a free society - the detention of journalists anywhere is unacceptable," Clinton tweeted.
One-time democracy icon Aung San Suu Kyi has been accused of backsliding in press freedom since her National League for Democracy (NLD) party took power in 2016. At least 11 journalists were arrested in Myanmar in 2017.
