A conclave was held from 2 to 6 February 1922 to elect a new pope to succeed Benedict XV, who had died on 22 January. Of the 60 eligible cardinal electors, all but seven attended. On the fourteenth ballot, the conclave elected Cardinal Achille Ratti, the archbishop of Milan. After accepting his election, he took the name Pius XI. During his first appearance on the main loggia of St. Peter's Basilica, he gave the traditional Urbi et Orbi ("to the city and to the world") blessing to the people in St. Peter's Square, which his predecessors had abstained from since the capture of Rome by Italy in 1870.

Four non-European cardinals did not participate in the conclave. Three of them arrived too late, and one did not attempt the journey. Three weeks after his election, Pius XI issued rules extending the time between the death of a pope and the start of the conclave in order to increase the likelihood that cardinals from distant locations could participate in the next conclave.

The previous five conclaves had produced a seesawing between conservatives and liberals, from the conservative Gregory XVI in 1831 to the initially liberal Pius IX. Pius IX had become a religious and political conservative by the time of his death in 1878, and he was succeeded by the more liberal Leo XIII, who on his death was succeeded by the theologically conservative Pius X, who strongly condemned modernism. In 1914, the more liberal Benedict XV was elected.

At the death of Benedict XV, there were 61 members of the College of Cardinals. Enrique Almaraz, the archbishop of Toledo, died the same day. Three of the remaining 60 cardinals did not attend the conclave for reasons of health: José Martín de Herrera, Giuseppe Prisco, and Lev Skrbenský z Hříště. Rio de Janeiro's Joaquim Cavalcanti knew he could not reach Rome in time for the conclave and did not attempt the journey. The other three non-European cardinals (William Henry O'Connell of Boston, Dennis Joseph Dougherty of Philadelphia, and Louis-Nazaire Bégin of Québec City) did not arrive in time to participate in the conclave.

Two-thirds of the non-Italian cardinals and some of the Italians wanted to delay the start of the conclave until at least one of the Americans arrived. Cardinal János Csernoch of Hungary told the other cardinals that "America is a vital part of the Church. It will be calamitous to deny her participation in the election of the pontiff. It will have a grave reaction among the American people; it will wound their pride and dignity." Cardinal Friedrich Gustav Piffl opposed proceeding without the Americans "for the sake of a technicality". The 53 cardinals who entered the conclave on 2 February, the eleventh day following the death of Benedict XV as required, were 31 Italians, five French, four Spanish, three German, three British, two Polish, two Austrian, one Hungarian, one Belgian, and one Dutch.

During his time as apostolic delegate to the United States, Archbishop Giovanni Bonzano sent $210,400.09 to the Holy See to ensure the conclave could occur.

The 1922 conclave was the most divided conclave in many years. While two of the previous three conclaves had lasted three days or less, the 1922 conclave lasted for five days. It took fourteen ballots for Achille Ratti, the archbishop of Milan, to reach the two-thirds majority needed for election. He had been made a cardinal and appointed archbishop of Milan just eight months earlier after a long academic career and less than three years in the diplomatic service of the Holy See.

At the conclave, the College of Cardinals was divided into two factions. One conservative faction favoring the policies and style of Pius X, known as the "irreconcilables" or "integrationists", was led by Secretary of the Holy Office Cardinal Rafael Merry del Val. The other more conciliatory faction favoring the policies and style of Benedict XV was led by Cardinal Camerlengo Pietro Gasparri, who had served as Benedict's secretary of state.