The sample survey on the small and medium enterprises (SME) covers the population of enterprises with 1 to 99 persons employed and answers to the request of SBS EU Council Regulation n. 58/97 (until the reference year 2007 in Nace Rev.1.1) and SBS EU Council Regulation n. 295/2008 (starting from the reference year 2008 in Nace Rev.2). The observation unit is the enterprise and the frame is represented by the Italian business register (Asia). The sampling design is a one stage stratified random sampling, with the strata defined by the combination of economic activity, size class of persons employed and administrative region. The main variables collected annually by an electronic questionnaire regard business competitivity, employment, personnel cost, investments. The data collected is treated with statistical procedures for assuring consistency and coherence and non-response technique, by integrating data from administrative sources. The estimation methodology is based on calibration, by using known totals from the business register (the number of the persons employed and enterprises).