Milk yield, conception rate of ewes, litter size and productive lifetime of ewes were identified as the most important traits for dairy sheep breeds in Slovakia. Sensitivity analyses established that the economic values of these traits are sensitive to differences in production circumstances. Consequently, the overall breeding objective should be calculated using the weighted average of the economic values of traits obtained in the most common production strategies of Slovak dairy sheep farms. Periodic adjustment of economic values is required after substantial changes in the trait levels in the population.