In this talk, I argue that the measurement of cattle behavior is a necessary aspect in the assessment of their welfare. Issues of behavioral deprivation have been central to the concern about animal welfare since the beginning and surveys have shown repeatedly that the public / consumers are particularly concerned about the inability of farm animals to perform natural behavior in intensive housing systems. Furthermore, early research showed that even farm animals subject to generations of artificial selection still show much of their natural behavior when given the opportunity to do so. Some of the most contentious issues in dairy cattle welfare involve primarily behavioral issues. Measures of animal behavior also add precision in animal welfare assessment. For example, common behavioral responses to illness provide one means for us to assess the relative impact on dairy cow welfare of various diseases. Behavioral based measures provide the best means we have at present of judging the acute emotional response of dairy cattle to short-term husbandry procedures and the longer term emotional state of the animals. However, to best use behavioral measures in animal welfare assessment, we need to better understand the causal and motivational bases of the behaviors. Finally, exploiting dairy cattle’s behavior provides a novel means of solving some husbandry problems, while giving animals a sense of control over their environment, potentially improving their welfare. Because of these matters, assessments of animal welfare that do not include behavioral measures do not provide a complete picture of the welfare of the animals.