Clifford, 71, was at North East Surrey Crematorium in south-west London, where his brother Bernard's funeral took place.
The disgraced PR guru wore a navy suit, pink shirt and sunglasses, and arrived and was taken away in a prison van.
Clifford was jailed for eight years after being convicted of a string of indecent assaults, carried out between 1977 and 1984, using his celebrity connections to lure women.
Passing sentence at Southwark Crown Court in May, Judge Anthony Leonard told Clifford his personality and position in the public eye were the reasons his crimes were not revealed earlier. The judge said that due to the historic nature of the offences, Clifford was charged under an act from 1956, which set the maximum term for each charge at two years.
The Ministry of Justice said it does not comment on individuals, but a spokeswoman said prisoners need to apply to attend a funeral and the prison assesses risk to the public and also looks at the prisoner's relationship to the dead person. If permission is granted, the prisoner is normally escorted to the funeral by staff.
Clifford has lodged an appeal against his sentence.