Rajab, who was detained in 2014 for tweets deemed insulting to the authorities before his release on health grounds, was apprehended in a dawn raid on his home in the mainly Shiite village of Bani Jamra near Manama, according to his family.
"Rajab was arrested from his house and his house was searched," Sumaya Rajab, his wife, posted on Twitter.
Signup to our newsletter and follow us on Facebook and Twitter!
The activist, who has led anti-government marches and heads the Bahrain Centre for Human Rights, had previously served two years in jail for taking part in unauthorised protests.
He was sentenced to six months in jail for his tweets but pardoned in July 2015 after King Hamad issued a royal pardon "for health reasons".
Bahrain, home to the US Navy's Fifth Fleet, has been rocked by unrest since security forces crushed Shiite-led protests in 2011 demanding a constitutional monarchy and an elected prime minister.
Washington had previously called for Rajab's release, while international rights groups have condemned the trials against opponents of the Sunni regime.