The current globally recognized comparative food and feed safety assessment paradigm for biotechnology-derived crops is a robust and comprehensive approach for evaluating the safety of both the inserted gene product and the resulting crop.  Incorporating many basic concepts from food safety, toxicology, nutrition, molecular biology, and plant breeding, this approach has been used effectively by scientists and regulatory agencies for 10?15 years.  Current and future challenges in agriculture include the need for improved yields, tolerance to biotic and abiotic stresses, and improved nutrition.  The next generation of biotechnology-derived crops may utilize regulatory proteins, such as transcription factors that modulate gene expression and/or endogenous plant pathways.  In this review, we discuss the applicability of the current safety assessment paradigm to biotechnology-derived crops developed using modifications involving regulatory proteins.  The growing literature describing the molecular biology underlying plant domestication and conventional breeding demonstrates the naturally occurring genetic variation found in plants, including significant variation in the classes, expression, and activity of regulatory proteins.  Specific examples of plant modifications involving insertion or altered expression of regulatory proteins are discussed as illustrative case studies supporting the conclusion that the current comparative safety assessment process is appropriate for these types of biotechnology-developed crops.