Nawaz Sharif arrived in his hometown, Lahore, to a boisterous and chaotic reception at the airport. With journalists and supporters crowding the arrival hall, Mr. Sharif told reporters that current conditions in Pakistan are not conducive for elections.
Mr. Sharif demanded a restoration of the democracy and for the country's deposed Supreme Court justices to be reinstated.
After supporters carried him on their shoulders through the packed arrival hall, Mr. Sharif boarded an armored car provided by the Saudi royal family for a procession to Lahore's Data Durbar shrine.
Mr. Sharif has been a fierce opponent of General Pervez Musharraf, since he ousted Mr. Sharif in a bloodless coup in 1999. The former prime minister was sentenced to life in prison in 2000 for corruption and other crimes, but the sentence was later commuted to 10 years in exile. Although his return appears to violate that sentence, officials allied with General Musharraf have said they do not expect Mr. Sharif to be arrested.
Mr. Sharif attempted to return from exile in September, but was swiftly sent back to Saudi Arabia. His party says the Saudi kingdom has now decided to end its participation in his exile.
Political analysts say the return of Mr. Sharif could prevent any political party from winning a majority of seats in January's parliamentary elections.
But several opposition parties say they are considering boycotting the elections.
Opposition politicians have been registering to run in the election, but maintain they may still withdraw by the December 15 deadline if General Musharraf does not meet their demands for ending emergency rule and restoring the judiciary.