Genetically engineered food products have several advantages over their conventional counterparts; i.e. improvement of production traits is rapid, and genetic information can be transferred across species. However, introduction of a new gene into food crops may lead to emergence of altered composition and nutritional value, allergenicity and toxicity. To meet the requirements to environmental and food safety, sale of GM foods in Taiwan must comply with regulations, guidelines and labelling of various governmental agencies. Among these agencies, the Department of Health is responsible for the safety and labelling of GM foods, and has promulgated regulations stipulating the labelling of food products containing GM ingredients. Our initial step on the mandatory labelling of GM foods would let consumers to decide to purchase GM products.