For providing systems to support decision making it is important to understand how farmers collect and manage decision information. Using data from a mail survey a ""three-information-area"" and ""four-system-type"" model was tested to describe Canterbury dairy farmer's information management structure. Those using computerised systems in every area were the largest group, but representing only 12% of farmers. Farmers using computerised systems in different information areas show similar characteristics in contrast to non-users, such as having farmed less years, being younger, having larger herds and bigger farms, being more educated, spending more time doing office work, involving more both farm adviser and accountant time, and being more profit oriented. Those who own computers, but do not use computerised information systems, are not statistically different from those not owning computers. The use of computers for managing feed and pasture information seems to be more restricted than for finance and livestock. The relationships among farm management computer use and the farmer's characteristics were checked using single statistical tests, regression and cluster analyses. The research findings are relevant for those aiming to improve farmer information management and also for farm software developers.