Anaerobic digestion of livestock manure is a manure treatment option with benefits. Raw manure is processed using a heated, oxygen free container, allowing digestion that began in the cow’s stomach to continue and be enhanced. Products of anaerobic digestion of livestock manure include a combustible gas (i.e. biogas), liquid effluent, and digested solids. The gas is often used for energy generation (electricity and or heat). The liquid effluent is a low-odor fertilizer with characteristics closer to commercial fertilizers that provide more flexibility to farmers in land application. This can often be substituted for the increasingly expensive commercial fertilizers. The phosphorus (P) rich digested solids are commonly used as bedding for cows, but also have value as soil supplements either on agricultural lands or for landscapers and greenhouses. Wisconsin continues to be one of the leading states in operating farm-based anaerobic digester systems. The Wisconsin Agricultural Biogas Casebook includes brief case studies of farm-based anaerobic digesters installed in Wisconsin. This report gives a snapshot with some history of the 17 operating anaerobic digester systems in Wisconsin as of June 2008. This information is presented to give those interested in digesters some insight into how these systems are working in Wisconsin. In addition, digester owners have generously shared experiences, ideas and innovations that may prove invaluable to those evaluating similar options for their farms. The sources chosen for information in compiling these case studies are: 1. digester owners – information on farm characteristics, operation, and experiences 2. technology providers – digester designs and characteristics, assumptions about the farm that went into designing the digesters, biogas utilization systems 3. utility representative – energy generation, power purchase agreements, interconnection issues