The results of a nationwide New Zealand survey into willingness to pay (WTP) for six different genetically modified (GM) food products were used to estimate market-level demand curves for the products. The raw results clearly indicate that different New Zealanders have different WTP for GM food. An estimated sigmoid regression curve showed that, with one exception, the type of GM product offered had little effect on WTP. This estimated demand curve was used to calculate the optimal uptake of GM crops, which is the percentage of total output that should be GM in order to maximise industry revenues.