Agriculture will inevitably always have a significant impact on the environment. For biotech crops to be accepted by the regulatory process, it is a statutory requirement in most countries to complete an environmental impact assessment. The assessment includes determining the frequency and potential impact of gene flow by pollination, the effects on friendly nontarget organisms within the environment, the consequences of introducing particular genes, and, in some countries, a consideration of the effect of biotech crops on wildlife biodiversity. Assessing environmental impact raises many important challenges, because frequently we are required to make assessments of a kind that have rarely been carried out for conventionally bred crops. Debates about how we measure environmental impact most effectively have highlighted the illogicality of detailed environmental assessments of biotech crops and little or no comparable assessment of conventionally bred crops. It is important that all kinds of agricultural crops are evaluated against an evolving vision for the future of agriculture and the environment over the coming decades. Biotech crops have the potential to aggravate or to alleviate the environment of the future. This can be through direct effects of the crop on the environment or through changes in management required to grow them. Our challenge is to develop biotechnology actively for the benefit of humankind and the environment.