Swiss tennis superstar Roger Federer said he was "extremely disappointed" to miss Olympics due to extensive rehabilitation after his knee surgery in February this year.
Argentina's football team at Olympics will be without their captain Lionel Messi, who retired from international football after the Copa America final in June.
Former world number one Tiger Woods in among the top golfers set to miss Rio Games. Woods has a back problem.
Russia has been hit by a doping scandal and Olympic champion pole vaulter Yelena Isinbayeva is one of the casualties of the ban. Russia's entire track and field team is barred from the Games.
US basketball team will miss the services of LeBron James (pictured, left). He was to take rest from the game.
India's five-time world boxing champion Mary Kom, who won bronze at last Games in 2012, failed to qualify. She was expecting a wild card entry but did not get.
American basketball team will also be without Kobe Bryant, who has retired from the sport.
World number one golfer Jason Day (pictured, right) of Australia is skipping the mega event due to fears of the Zika virus.
India's boxing star Vijender Singh will not be in Rio De Janeiro as he has turned pro. Though professional boxers are allowed this time, Vijender could not make it as Vikas Krishnan made the cut in 75 kg category.
Olympic bronze medallist Sushil Kumar of India will not be going to Rio De Janeiro. He was not selected in the team. Initially, there was controversy over his non-selection but the matter is settled now.