A flight of Thai Airways carrying his body landed at Hazrat Shahjalal International Airport around 12:42am, said BNP chairperson's media wing member Sayrul Kabir Khan.
His first namaz-e-janaza will be held after Zohr prayers at Dormitory Jame
Mosque in Green Road area, said his elder brother Dr Mahbub Ullah.
His second janaza will be held after Asr prayers at the Jatiya Press Club and then he will be buried at Mirpur Martyred Intellectuals' graveyard.
The journalist, who was on life support at the Bumrungrad International Hospital, breathed his last around 10:05 am (Bangladesh time) at the age of 69.
"My father is no more. He breathed his last at 10:05 am today (Saturday). We are taking preparations to take his body home on completion necessary formalities," his daughter Nusrat Humaira told UNB.
Mahfuz Ullah had been suffering from various complications in heart, kidney and lung. He was flown to Thailand on April 10 for advanced treatment.
Mahfuz Ullah was politically active since his student life and had taken part in the 11-point movement. He was expelled from Dhaka College for his activism.
Born in Noakhali in 1950, Mahfuz Ullah obtained MA degrees in physics and journalism from Dhaka University. He got involved in journalism when he was a student and had been associated with popular weekly 'Bichitra' since its inception in 1972.
He also worked at Bangladesh Deputy High Commission in Kolkata as a 'China expert' and taught at Dhaka University's journalism department. MahfuzUllah had hosted radio and television shows and been involved with leading Bangla and English dailies in Bangladesh.
He has also authored more than 50 books in Bangla and English, apart from editing a number of others.
Books edited by him include the biographies of BNP founder Ziaur Rahman and Khaleda Zia, the mass uprising of 1969, insurgency in Assam, and post-independent Bangladesh.