The aim of the paper is to assess diversification dynamics of the agrarian structure of voivodeships in years 1996-2008. The calculations were made on the basis of statistical data obtained from the Central Statistical Office—the number and area of farms have been grouped by voivodeships. With the use of a fuzzy classification method, voivodeships have been divided into groups of similar agrarian structures according to data of 1996, 2002 and 2008. As a result, 4 groups comprising the same voivodeships in each year have been distinguished. Group I con- sists of Malopolskie, Śląskie and Podkarpackie voivodeships. It is characterized by the highest degree of fragmentation of the agrarian structure. In 2008 around 82% of farms had the area of 1-5 hectares, while 14.4% of them had the area of 5-10 hectares. The remaining farms repre- sent a very small proportion: 10-20 hectares—3.3%, 20-50 hectares—1.1%, more than 50 hec­tares—0.3%. Group II consists of Łodzkie, Mazowieckie and Lubelskie voivodeships, where structure indices are as follows: 51.5%, 29.2%, 14%, 4.2% and 0.5%. The lowest degree of fragmentation is observed in group III, comprising Podlaskie, Kujawsko-Pomorskie, Pomorskie, Warminsko-Mazurskie and Wielkopolskie voivodeships. The average structure is more regular in this group: 35.5%, 23%, 25.2%, 13.3% and 3.1%. Group IV consists of Lubuskie, Dolnośląskie and Opolskie voivodeships and average structure indices are as follows: 57%, 19.9%, 12.5%, 7.3% and 3.2%.