A conclave held from 8 October to 5 December 1590 ended with the election of Gregory XIV was elected as the new pope. This conclave was marked by significant interference from King Philip II of Spain.

Urban VII was elected as pope on 15 September 1590. On 27 September 1590, he died due to malaria infection after only 12 days of his pontificate before he could be crowned, giving him the shortest papacy in history. His death was deeply mourned by the poor from Rome who inherited his wealth.

The conclave, after the death of Urban VII, was attended by all the cardinals who took part in his election, with the exception of Cardinal Federico Cornaro (who had died on 4 October). Protodeacon Andreas von Österreich and Camerlengo Enrico Caetani also came to Rome. Of the 65 total cardinals, 54 took part in conclave.:

Twenty-four electors were nominees of Sixtus V, fifteen of Gregory XIII, six of Pius V, eight of Pius IV, and one of Julius III.

Eleven cardinals were absent:

Seven of them were appointed by Gregory XIII and four by Sixtus V.

As during the previous conclave there were three large factions:

There were two small groups practising nepotism. One was related to Pius IV (Sitticus von Hohenems, Serbelloni, Gesualdo i Avalos d'Aragona) and the other to Pius V (Bonelli, Albani). Due to the small size of the groups, they almost did not play any major role and the majority of nominees of these Popes became part of the Spanish faction.