While the estimated global area of transgenic or genetically modified (GM) crops continues to increase the vast majority of acreage (99 per cent) remains confined to just four countries, namely the US, Argentina, Canada and China. In most developing countries it is still not legal to plant GM crops on a commercial basis, largely due to hold-ups in the approval process.  Even countries that have in the past moved rapidly on the adoption of GM organisms (GMOs), including China and Argentina, are now slowing down the approval processes. While the regulatory blockages are usually justified on biosafety grounds, trade concerns appear to play an increasing role with countries fearing export losses in markets such as the EU, Japan and Korea where the import regulations for GMOs continue to be tightened. The ongoing trade dispute between the US and the EU's continued de facto moratorium on the approval of new GMOs is also adding to the prevailing uncertainty in the international commodities market.In this context, the first part of this paper will outline regulations affecting the import of GMOs and GM products in selected countries, including import restrictions, risk assessment provisions and labelling requirements. While most of the attention will focus on some of the major OECD countries, including the EU, the US and Australia/New Zealand, the paper will also review regulations in key developing countries in Asia, Latin America and Africa. The second part will look at possible conflicts between national import regulations and WTO rules, in particular regarding the current and proposed EU regulations. To this end, the section will briefly outline the relevant WTO agreements; assess the trade-restrictiveness of mandatory traceability and labelling requirements; evaluate whether GMO regulations covering substantially equivalent GM products might be trade-discriminatory; look at the role of precaution as a justification for an import ban on GMOs, and briefly discuss the Cartagena Protocol on Biosafety and how its provisions might impact on a possible dispute at the WTO.