Despite the evidence of benefits from GM papaya\'s adoption in other countries, concerns over the loss of export markets and health and environmental risks have led to great uncertainty and indecision about policies to support biotechnology in Thailand. Since 2001, field trials have been banned and the use of transgenic plants for production, consumption, or commercialization has been prohibited. Field trials in government fields were reinstated in December 2007, but agricultural biotechnology policies remain unclear. This article estimates what the economic impact of the adoption of GM papaya would be if Thailand were to authorize the use of GM technology. We estimate that total economic surplus in the range of $650 million to $1.5 billion USD would be generated within the first 10 years of adoption. These benefits would accrue primarily to small-scale papaya farmers and would accrue even with the loss of export markets.