Robles made contact with China’s Liu Xiang and was disqualified after the Chinese appealed, handing Jason Richardson the gold and Liu the silver.
An appeal from the Cuban team was rejected and Britain’s Andy Turner was awarded the bronze medal.
Usain Bolt was disqualified from the 100m for a false start on Sunday.
Olympic champion and world record holder Robles brushed Liu’s arm, causing him to trip on the final hurdle and finish in 13.27 seconds, behind Richardson, who clocked 13.16.
“Robles hit me twice, at the ninth hurdle he pulled at me but I’m sure it wasn’t intentional,” said Liu, who won 2004 Olympic gold and the 2007 world title. “I lost my balance when I came to the 10th hurdle because of the bump. If not for the incident, I would have been the gold medallist.”
Meanwhile, in the women’s 400m final Amantle Montsho won Botswana’s first ever medal at the World Championships.
Montsho held American Allyson Felix on the line to win in a time of 49.56 seconds, just three-hundredths of a second ahead of Felix, with Russia’s Anastasiya Kapachinskaya taking bronze.
Oscar Pistorius saw his historic appearance at the championships come to an end as he failed to make the final of the 400m.
The 24-year-old South African, the first amputee athlete ever to compete in the competition, finished last in his semi-final.
Pistorius, whose carbon fibre blades have provoked great debate over whether they give him an unfair advantage, clocked 46.19 seconds.
Defending champion LaShawn Merritt was the fastest inqualifying, timed in 44.76 seconds after recently returning from a doping ban.
Also through to the final are Belgian twins Jonathan and Kevin Borlee, Grenadan pair Kirani James and Rondell Bartholomew, Tabarie Henry of the US Virgin Islands, Jamaica’s Jermaine Gonzales and Nigeria-born Femi Ogunode of Qatar.
In the last final of the evening American Carmelita Jeter raced to gold in the women’s 100m.
She made a superb start and finished in 10.90 seconds, beating Jamaica’s Veronica Campbell-Brown by seven-hundredths of a second, with Trinidadian Kelly-Ann Baptiste third.
Koji Murofushi earned a surprise gold medal in the hammer with a throw of 81.24 metres yesterday to give Japan its first title of the championships.
And in the pole vault, Poland’s Pawel Wojciechowski took gold following a leap of 5.90m.