An economic evaluation of two Australian Centre for International Agricultural Research (ACIAR) projects in the area of postharvest technology for tropical fruits was undertaken. This evaluation considered a 30 year time period from the first year of investment and assumed a discount rate of 5 per cent. The estimate of the net present value of the research and development investment was $93 million expressed in 1996/97 terms. The benefit–cost ratio was 38:1 and the internal rate of return estimated at 64 per cent. If benefits realised by 1996/97 were considered, the net present value was $30 million, the benefit–cost ratio was 13:1, and the internal rate of return was 63 per cent. Benefits accrued to both Thailand and Australia, with the proportion of benefits attributed 52 per cent to Thailand and 48 per cent to Australia. The commodities to which benefits mostly related were mangoes in the case of Australia, and longans and durians in the case of Thailand. One of the technologies developed in Thailand for longans is now starting to be used in Australia in the developing longan industry.