The aim of this study was to evaluate the relationship between the level and changes of body condition at calving and fertility in high-producting dairy cows. The observation was performed in the herd of 655 Holstein cows housed on one farm. The averagemilk production within the standardized 305 days lactation was 11,390 kg milk with 3.81 % of fat and 3.18 % of protein. 277 cows calved in the period from July 2008 till January 2009 were evaluated. It was evident that the level of cows?body condition atcalving had the influence on the BCS changes in the beginning of lactation and also affected the course of the first third of lactation. Cows with lower BCS at calving showed higher daily milk yields and they were able to maintain body condition withoutmarked variances or to retrieve body fat reserves shortly after the peak of lactation.