"Mannada breathed his last around 4 a.m. after his condition suddenly deteriorated in the wee hours though he was on a ventilator in the intensive care unit," Narayana Hospital spokesman K.S.Vasuki told IANS.
The multi-lingual singer, who has been ailing for four months, leaves behind two daughters -- Rama and Sumita.
"Dey's eldest daughter (Rama) rushed to the hospital and was at his bedside when the end came after we alerted her about her father's deteriorating condition," Vasuki said.
According to Dey's family sources, Sumita lives in the US.
Dey's wife Sulochana Kumaran passed away here in January 2012 due to cancer.
Dey was admitted to the super specialty hospital in early July after he complained of lung infection and was undergoing treatment for a respiratory disease.
"Dey's body will be kept at Ravindra Kalkshetra in the city centre from 10am to 12noon for the public to pay their last respects and homage," a family friend said.
The family plans to perform Dey's last rites at Hebbal crematorium in northwest of the city by Thursday evening.
News of Dey's passing away shocked thousands of his fans, especially the music industry and the million-strong Bengali community in this tech hub.
Dey was in the same hospital for about 20 days in May a week after West Bengal Chief Minister Mamata Banerjee honoured him May 1 with Bengal's Vishesh Maha Sangeet Samman award in recognition of his yeomen service to the world of music and the film industry for over seven decades.
Mannada, whose original name was Prabodh Chandra Dey, has to his credit over a record 3,500 songs in an illustrious career spanning seven decades since 1943. His oeuvre boasts of a range of songs; from romantic numbers to classical to fun songs.
Dey was also honoured with the Dadasaheb Phalke Award, the country's highest award in the film world, in 2007.
He was also recipient of several awards, including Padma Shri and Padma Bhusan.