The study presents changes in cows breeding and milk production in 1990-2010 with distinction of the period of intense system changes, and pre-accession and post-accession periods. The analysis was based on CSO data, in particular on data from Agricultural Census of 1996, 2002 and 2010. The analysis indicates that in this period there was a considerable decrease in the number of farms keeping cows, and in the number of cows. However, the dynamics of these processes was greatly varied in certain years, as well as significantly regionally diversified. Within the period of intense system changes (1990-1996), the rapid yield compression in cows breeding, and liquidation of state agricultural farms revealed not only decrease in the number of farms keeping cows and in the number of cow, but also deconcentration in cows breeding and recourse in improvement of herd of cows. In the pre-accession period (1996-2004), at the time of decrease, in the number of farms keeping cows and in the number of cows, the process of concentration and stabilisation was gradually shaped. The intensifying competition on the milk market and increasing requirements of milk processing plants are the driving force for these processes. In the post-accession period (due to improvement of profitability of milk production and farms’ income) the above-mentioned processes were noticeably intensified. Wielkopolskie and Kujawsko-Pomorskie Voivodeships (with good agrarian structure and good agricultural condition) gradually join the central-eastern region, leading in the development of cows breeding and milk production. The recourse region, so far covering three south eastern voivodeships, is broadening now covering Lubelskie Voivodeship (also characterised with fragmented agrarian structure). At the same time, there is an improvement trend in cows breeding and milk production in the western and northern region, i.e. in the so-called poststat farm region. Such improvement is based on the dynamic development of cows breeding and milk production in large farms keeping great herds of cows.