Sweden has officially become the 32nd member of Nato after it completed its accession process in Washington.
The handover of documents took place at a ceremony two years after Sweden applied to join the military alliance following Russia's full-scale invasion of Ukraine.
Swedish Prime Minister Ulf Kristersson said that "unity and solidarity" would be Sweden's "guiding lights".
"Good things come to those who wait," US Secretary of State Anthony Blinken said.