In response to an invitation from the Permanent Mission of Portugal to the OSCE, and based on the recommendation of a needs assessment mission carried out from 24 to 26 June, ODIHR deployed an election assessment mission for the 27 September parliamentary elections.

The mission was led by Jean-Pierre Kingsley and consisted of 12 election experts from 11 OSCE participating States.

According to the mission's final report: "The elections were conducted in a manner which reflected Portugal’s established democratic tradition, respect for political pluralism and fundamental freedoms as well as a high level of public confidence in the overall process. Voters enjoyed a wide and genuine choice of political parties. Some aspects of the political system may nevertheless merit review."