Mr Musharraf said emergency rule was in the national interest
The Commonwealth has decided to readmit Pakistan, suspended six months ago after the imposition of emergency rule.
A statement issued in London said the suspension would be lifted immediately.
Pakistan was suspended last November after President Pervez Musharraf failed to meet a deadline to lift a state of emergency and resign as army chief.
He quit the army in November, and ended emergency rule the following month. General elections held in February were won by the opposition.
A spokesman for the Commonwealth noted that Pakistan now had a democratically-elected government, and that President Musharraf had resigned as head of the army.
"The government of Pakistan has taken positive steps to fulfil its obligations in accordance with Commonwealth fundamental values and principles," the statement said.
Elections had been due in January but were delayed by the assassination of former Prime Minister Benazir Bhutto.
The vote went ahead in February with her Pakistan People's Party emerging with most votes.
It is the second time that Pakistan has been barred by the Commonwealth. The country was suspended in 1999, after Gen Musharraf seized power in a coup.
It was reinstated in 2004.
The Commonwealth groups together about 1.8bn people, most of them in former British colonies.
Being suspended means a country cannot take part in Commonwealth meetings and the organisation's aid projects in the country are halted.