He was 79. He is survived by his wife Neela Devi, son Aditya Raj and daughter Kanchan Desai.
According to the sources, he was on dialysis for the last few years and was undergoing the procedure at least thrice a week. He was yesterday admitted to the ICU of the hospital.
The actor, who made his debut in Bollywood in 1953, when the film Jeevan Jyoti was released, carved out a niche for himself with the superhit Junglee in 1961.
His new image took ground and his subsequent films were all in this genre later.
Kapoor, hailed as 'Elvis Presley of India', joined the silver screen at a time when his elder brother Raj Kapoor, Dev Anand and Dilip Kumar were the reigning trio.
Kapoor was suffering from chronic renal failure, family sources said.
The funeral will take place tomorrow morning, they said.
Born Shamsher Raj Kapoor on October 21, 1931, Kapoor was the second son of veteran theatre and film actor Prithviraj Kapoor.
Despite his family background, Shammi's entry into Bollywood was initially not successful even though he worked with major heroines like Madhubala in Rail ka Dibba, Suraiya in Shama Parwana and Nalini Jaywant in Hum Sab Chor Hai.
His initial movies flopped at the Box Office. He reinvented himself with Tumsa Nahi Dekha cutting his hair in the famous duck-tail style of the 50s and never looked back.
With the success of Junglee in 1961, an entire decade reeled under its colourful impact.
Shammi heralded the swinging 60s and a large part of his appeal was primarily due to the immensely catchy and upbeat numbers like Suku Suku, O Haseena Zulfo Wali, Aaj Kal Tere Mere Pyar Ke Charche, Aaja Aaja Main Hoon Pyar Tera where he was at his boisterous best.
Even though success came with light-weight tales like Kashmir Ki Kali, Rajkumar, Jaanwar and An Evening in Paris, his performances in films like Junglee, Badtameez, Bluff Master, Pagla Kahin Ka, Teesri Manzil, Brahmachari silenced his critics.
Andaz, which released in 1971, was his last movie as a leading man but his character roles in Vidhata, Hero and Prem Rog were well received.
His latest onscreen stint was a cameo in grand nephew Ranbir Kapoor's yet-to-be-released film Rockstar directed by Imtiaz Ali.
Shammi was a computer aficionado and in his last years veered towards spiritualism.
Tributes on the news of his death have poured in thick and fast. Some of the reactions:
"Shri Kapoor was one of the veteran actors, who adorned Hindi cinema. He delighted Hindi cinema fans with his vivacious acting. He shall always be remembered by a generation of film watchers. His acting was best exemplified through the popular songs in the movies Junglee, Rajkumar, Teesri Manzil, Tumsa Nahi Dekha, Kashmir Ki Kali, Brahmachari, Vidhata and others. In his death, the film industry has lost a creative talent."
-- Pratibha Patil, President
I am sad to learn of Shammi Kapoor's demise. He was an accomplished actor who entertained millions and millions of fans in India and abroad. I share his family's grief.
--Manmohan Singh, Prime MinisterShammi Kapoor ji passed away this morning at 5:15 am ..Rushing there now .. The flamboyance and joie de vivre'of the Industry lost!...An entire life full of optimism and happy spirit, caring loving to all ... Now suddenly silent.
--Amitabh Bachchan, Actor
Shammi Kapoor has left a lasting imprint in the film industry through his strong personality and acting.
His death has caused an irreparable void in the film industry.Kapoor's personality and acting will always be remembered by his admirers.
--Nitish Kumar, Chief Minister, Bihar.Shammi Kapoor ji was one of d 1st Youth Icons from Cinema. He liberated actors from being stereotypes. Will miss his STYLE and SUBSTANCE.
Shammiji had a unique style of acting, dancing and dialogue delivery that endeared him to the youth. Even after his retirement from the film industry, Shammiji involved himself with various meaningful initiatives for the benefit of society...Shammiji will remain Hero for the people of my generation. I pay my respects to the fond memory of this versatile actor and fine human being.
--K Sankaranarayanan, Maharashtra Governor
--Anupam Kher, Veteran Actor
I am saddened with the death of Shammi Kapoorji. He was a big star of the film industry and also a very good human being. He was very lively person...Courageous, faced all difficulties very bravely...Also, Shammiji was a very good singer. He has learnt music and used to call me his sister. I am feeling awful by his death and may his soul rest in peace.
--Lata Mangeshkar, Singer
I am a great admirer and a huge fan of Shammiji. His energy on screen is a treat to watch and I have loved every bit of it. His demise is a huge loss to the film industry and fraternity and mainly to his millions of fans. I convey my heart felt condolences to all in his family. O mere sona ..You will always live in our hearts.
--Rajinikanth, Tamil actor
One of the finest and strongest men I knew...We will truly miss you shammi uncle....RIP.
--Karan Johar, Film maker
Mr. Shammi Kapoor. Never before - Never again. Thank you for the wonderful cinematic memories and life lessons. RIP.
--Farhan Akhtar, Actor-Singer-Director
The narrative of Shammi Kapoor will not end with his passing away. His movies will continue to enchant the future generations!
--Mahesh Bhatt, Filmmaker
The great iconic Shammi Kapoor who defined an era n influenced music, dance n song even today has passed away, leaving a hollow void.
--Shekhar Kapur, Film Maker
He was an inspiration not just for his style and the films he did, but also his attitude towards life...We will miss you Shammi uncle.
--Deepika Padukone, Actress
Shammi Kapoor was a superstar of our era. His dance style was rage in our times. He was a fatherly figure for film industry. This is a big loss to the film fraternity.
-- Vilasrao Deshmukh, Union Minister for Science and Technology
The Industry has lost an iconic figure.
-- Prithviraj Chavan, Maharashtra Chief Minister
Shammi Kapoor's death is a sad day for Bollywood.
--Sushil Kumar Shinde, Union Power Minister
With the demise of Shammi Kapoor, a colourful era of the Hindi film industry has come to an end.
--Ajit Pawar, Maharashtra deputy Chief Minister
Sad to hear the demise of Shammiji, the YAHOO of Indian Cinema. Your charmful exuberance and full of life style will forever be missed by all of us, RIP.
--Madhur Bhandarkar, Film maker
Tremendous entertainer. Also one of the first champions of internet in India. RIP Shammi Kapoor. Shammi ji no one can take the place of all the "Yahoos" of our Indian hearts who loved you ... You will be missed deeply by us all.
--Celina Jaitly, Actress
Another legend passes away..Shammiji Kapoor..Such a jovial and positive person..Had the good fortune of interacting with him..Rest in peace.
--Aftab Shivdasani, Actor
Deeply saddened at Shammi Kapoor's passing away. So full of life and energy on screen now no more, we loved you so much..May you rest in peace.
--Tisca Chopra, Actress
Mr. Shammi Kapoor, RIP. You danced like nobody was watching.
--Vishal Dadlani, Music Director-Singer
RIP SHAMMI KAPOOR- the most stylish actor ever-we love you and we will miss you.
--Riteish Deshmukh, Actor
What a legacy of great music was associated with Shammiji.
--Shreya Ghoshal, Singer
RIP Shammi Ji. End of a legend.
--R Madhavan, Actor
Sometimes no amount of kind words can compensate for a loss! bhole baba ki jai shammi maharajji.. He was our guruji..I am at a loss.. Nothing will ever fill the void u have left. Im sorry i didnt try RESSEE.. But will do.. Only for you.. R.I.P.
--Priyanka Chopra, Actress
"I am saddened by the demise of Shammi Kapoor. Even though he is no more with us, his work is something that cannot be forgotten. He had a unique way of dancing... He had a different identity. He was well-versed with the latest technology and had an in-depth knowledge about everything. He was a tech-wizard. I have seen his films like 'Tumsa Nahi Dekha' and 'Rajkumar' among others.
-- Chaggan Bhujbal, NCP Leader
(reactions on Twitter have not been edited)