This article outlines both ecological and socioeconomic issues involved in the development and use of GMOs. It’s argued that while initially new GMOs add to the global stock of biodiversity, in the long-term they result in a decline in biodiversity. Various mechanisms that bring about this decline in genetic diversity are identified. It is suggested that due to evolutionary forces, the desirable genetic properties of some GMO may be eroded in the long-term. They are unlikely to be sustained in their ecological effectiveness forever. The economics of developing and marketing of GMOs is given particular attention. When their development is left to private enterprise, it is found that the economics of developing and marketing GMOs favours large enterprises as primary suppliers. In marketing, there are also preferences for sales of GMOs to larger-sized commercial farms rather than smaller-sized ones. GMOs that are favoured for development are in demand for use in large agricultural markets, many of which are located in higher income countries. Aspects of the patenting of GMOs, co-evolution, various social conflicts in the use of GMOs and legal liability for damages caused by the development and use of GMOs are discussed both from a socioeconomic and biosafety point of view.