The aim of the study was to evaluate the behavioural changes during the adaptation process in two dairy herds after their transition from tied housing to loose housing. In original farms cows were kept in similar tied systems with the difference that herd I (n=380) did not graze during the summer. Herd II (n=51) was taken to the new loose housing system directly after the grazing period ended. After introduction to the loose housing environment, herd I was divided into four groups, whereas the composition of herd II remained constant. In both farms cows were milked and fed twice daily. The study was conducted over one month with four five-day observation periods. Cows were observed between milking times (12.00-16.00). All the following behaviours were recorded with instantaneous recordings at 10 minute intervals during the study: lying, eating, walking, sleeping, ruminating and vocalizing. Of social behaviours, aggression and allogrooming were studied. Data were analysed with the binomial generalised linear models considering effects of period, farm and farm*period interaction using the SAS procedure GLIMMIX. Preliminary results showed that during the first observation period cows in farm one vocalized more (p<0.001) than in farm two (2.9% and 1,4%, respectively). At the same time cows from farm one showed less exploring and ruminating behaviour than cows from farm two (p<0.001; 0,9% and 2,5%; 17,9% and 23,9%, respectively). During later periods the vocalizing and exploring behaviours decreased in both farms whereas the rumination increased. Grooming and allogrooming were performed more by cows from farm one and those behaviours increased gradually in both farms during the study. It was concluded that the adaptation process in both farms lasted approximately three weeks and cows from the second farm that were introduced to the new environment from pasture were less stressed and adapted faster with the new environment.