This paper tackles the framework used to carry out the 2011 population and housing censuses in Portugal. It highlits the fundamental options regarding the use of internet to fill in the questionnaires, the buildings geocoding during the fieldwork and the dissemination program, in particular the dissemination of preliminary
results.

The response rate by internet reached 50,5% of resident population. Geocoding of residential buildings was fully carried out and this information provides a very strong potential on the use of censuses data, including the comparison with the previous since 1981.

Preliminary results of 2011 census point out to a generalised increase in the main data at the national level: resident population increased 1,9%; households increasead 11,6%, as well as housing units by 16,3% and residential building by 12,4%. These growings have intensified the concentration of population in the coast line while the inland reached significant losses of population.

Keywords: Population and Housing Censuses; 2011 Census; Internet Reponses; Building Geocoding