An economic evaluation of three ACIAR projects whose primary objective was to improve postharvest grain drying in Thailand and Australia is provided in this report. During 1983–1996, ACIAR invested A$1.2 million in research designed to improve grain drying in these countries. Based on current adoption, the investment has resulted in a realised net present value of A$3.6 million. A benefit–cost ratio of 3:1 was estimated for the projects. In other words, for each dollar invested, three dollars of project benefits have resulted. A high proportion of realised benefits was estimated to accrue to Australian rice producers, through reduced grain drying costs, while benefits have also been captured by the Thai rice production industry through reduced postharvest losses. Based on projected levels of future adoption, it was estimated that a project net present value of A$18.4 million could be achieved in Australia and Thailand. Several other countries such as Indonesia, the Philippines and Vietnam could also benefit from the technology developed in these projects. These benefits have not been quantified as part of this evaluation. Their inclusion would increase the value of ACIAR-supported grain drying research.