Bulk-tank milk (BTM) analysis is now widely accepted as a useful tool for evaluating milk quality and monitoring udder-health status in a herd. Bacterial and somatic cell count (SCC) estimation of BTM, when done repeatedly over a period of time, can become a significant knowledge base. When interpreted within the context of the farm's management practices, this information provides a basis for evaluating current and potential milk quality and mastitis problems in a herd. This article describes the process of using BTM analysis to make decisions on improving milk quality and herd udder health. It should be kept in mind that although individual cow samples for milk culture and SCC are more definitive for diagnosis and monitoring of udder health, BTM analysis is less expensive, more convenient, and faster than testing milk samples from individual animals or groups of cows.