The necessary data on agriculture must be available for public and private decision-makers in the agricultural sector to use agricultural information for decision-making, solve problems or increase their knowledge. As a result of the deregulation of the agricultural marketing sector in South Africa, the supply of these data decreased. Also, the needs for data on agriculture of the various decision-makers, i.e. the policy-makers, researchers, agricultural service industries as well as the farmers and extension officers, changed. Since information systems are based on the needs of the decision-makers, the need for data on agriculture should be determined before either existing methodologies are improved or new methodologies are introduced to increase the supply of data on agriculture in South Africa.