An overview is presented of the analytical steps that may be needed to determine the presence of genetically modified organisms (GMOs) or for analysis of GMO-derived produce. The analytical aspects necessary for compliance with labeling regulations are discussed along with bottlenecks that may develop when a plant product or a food sample is analyzed for conformity with current European Union GMO legislation. In addition to sampling and testing, other topics deal with complications that arise from biological and agricultural realities that may influence testing capabilities. The issues presented are intended to serve as elements to examine the different challenges that enforcement laboratories might face.