The application of engineered nanomaterials in food contact materials (FCMs) is considered a promising tool for improving functionality, but knowledge about exposure and toxicity remains limited. This chapter presents an overview of published studies on migration testing and the analytical possibilities and difficulties in determining the release of nanoparticles from FCMs. The evaluation of the literature shows that most studies of migration testing have dealt with the release of silver nanoparticles and a much smaller number with the release of nanoclays and other nanomaterials. Analytical methods for detecting nanoparticle release include scanning and transmission electron microscopy techniques to detect particles, atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry and especially inductively coupled plasma mass spectrometry (ICP-MS) to determine total element concentrations and combined techniques such as asymmetric flow-field flow fractionation-multi-angle light scattering-ICP-MS to detect nanoparticle size and concentration. In recent years, single-particle ICP-MS has been introduced as a technique that can determine nanoparticulate and ionic material in one analysis. So far, the migration studies found in the literature ignore release mechanism questions and improved analytical techniques are required to answers such questions.