Popular novelist and playwright Nguyen Quang Lap, whose blog often includes posts that are critical of the government, told dpa on Thursday he was allowed to go home two days earlier pending further investigation by the government.
"During detention I was treated well. My health is fine, the food was fine. Just one thing: I had to sleep on the cement ground," he said.
Lap was partially paralysed in a motorbike accident in 2001 and there were concerns about his health when he was arrested in November.
Another blogger, Hong Le Tho, 65, was released Wednesday, according to the Vietnamese prime minister's website.
Tho remains under investigation over his site "Nguoi Lot Gach," which means bricklayer.
Such releases are uncommon in Vietnam, which is often criticised by rights groups and foreign governments for targeting bloggers.
In the World Press Freedom Index released by Reporters Without Borders on Thursday, Vietnam ranks 175 out of 180 countries, just above China.
The government says it holds no political prisoners, only criminals or suspects.