Khoso said the completion of the election process has put to rest those critics who were skeptic about the polls, Xinhua cited the prime minister's office as saying.
The prime minister congratulated all political parties and candidates for participating in the elections.
Khoso appreciated the Election Commission of Pakistan, law enforcement agencies, federal and provincial authorities, media and the civil society for their role and cooperation with the caretaker government in holding the elections in a free and fair manner.
The exact number of people who voted was not immediately clear. But officials and reports spoke of a mammoth turnout. Pakistan has 86 million voters.
Voting was held for 269 of the 342 seats of the National Assembly and 728 seats in the assemblies of Punjab, Sindh, Balochistan and Khyber Pakhtunkhwa.