The agricultural activity in Galicia, NW Spain, is carried out on farms that are characterized by a diversity of land uses and production models, a variety of sizes, and considerable geographical dispersion. Any attempt of agricultural production planning that aims to characterize the production models requires a methodology for analysing data and obtaining technical-economic results from the farms present in the different areas. The analysis models based on average statistical data are limited because they represent farms that do not exist in reality. This study develops a procedure to characterize and group farms into different types according to the following basic variables: land uses, size classes and production systems. The source of information used in this study was the microdata included in the Agricultural Census of 1999. The tools used were Microsoft Access, Microsoft Excel, and an application that was developed by using Microsoft Visual Basic.