Interest in automatic flood irrigation is strong, given the labour and lifestyle benefits it can provide. An economic analysis of three automated flood irrigation systems for a dairy farm in northern Victorian indicated that automatic irrigation can be a profitable labour saving investment in many cases. However, profitability was sensitive to the amount and value of the labour saved. Pneumatic and timer systems were good investments regardless of the area they were installed to service. The supervisory control and data acquisition (SCADA) system was a good investment when more than 50 ha were serviced by the system. Irrigation water savings are unlikely to have a significant effect on the profitability of automatic irrigation, particularly if the price of water is under $100/ML. The labour efficiency of the irrigation system before automation has an important effect on the magnitude of benefits that might be achieved by automation. Larger bay sizes and fewer bay outlets enable the capital cost of automatic irrigation to be substantially decreased. However, this reduces the economic advantage of automatic irrigation systems as the labour savings are reduced.