Modi and Sharif warmly embraced one another as he got off the Indian Air Force plane and extended birthday greetings to the Pakistani leader at the Allama Iqbal International Airport.
Sharif's brother and Punjab Chief Minister Shahbaz Sharif and Pakistani Finance Minister Ishaq Dar were in the receiving party. The Indian envoy, TCA Raghavan, was also present.
Modi, who had spoken to Sharif earlier in the day from Kabul and wished him birthday greetings, is heading a 120-member delegation, officials said.
It is Modi's first visit to Pakistan and the first trip by an Indian prime minister to the country in 11 years.
National Security Adviser Ajit Doval is among those accompanying Modi, who later took off in a helicopter with Sharif for talks at his ancestral house near Lahore.