National population and housing census (NPHC) provides one of the  most major approach for  getting a general picture on socio-economic characteristics of the countries for planning, monitoring and evaluating national and regional services and activities. Nowadays, most countries implement the  NPHC every 5 or 10 years.

In the Islamic Republic of  Iran, based on Article 4 of the Act of the Statistical Centre of Iran (SCI), the  census shall be implemented once every 10 years according to the Presidential  decree. So far there have been 5 incidences  of population census in Iran in the years 1956, 1966,  1976, 1986, and 1996; all taken in accordance with scientific methods. Moreover, the SCI is going to take its forthcoming population and  housing census at the end  of Oct. 2006.