During the last decade, the area of biotech crops modified for agronomic input traits (e.g., herbicide tolerance and insect protection) has increased to 90 million ha/year, grown by over 8 million farmers in a total of 17 countries.  As adoption of these improved agronomic trait biotech crops has grown, so has interest in biotech crops that have improved nutritional characteristics for use as feed and food.  A previous publication by the International Life Sciences Institute (ILSI) reported on the principles and concepts proposed for the nutritional and safety assessments of foods and feeds nutritionally improved through biotechnology.  In this paper, the guidelines and principles recommended in the earlier publication are discussed relative to a specific case study, Lysine maize.  Lysine maize is a feed ingredient with enhanced nutritional characteristics for poultry and swine and provides an alternative to the need for addition of supplemental lysine to some diets for these animals.  The 2004 Task Force of the ILSI has also applied the concepts from that report to 4 other case studies: sweet potato enriched in provitamin A (2 examples, one using biotechnology and one using conventional breeding); Golden Rice 2; double-embryo maize; and ASP-1 enhanced protein sweet potato.