Characterization techniques to study scaffolds’ biocompatibility and their degradation in the body are presented. The relevance that simulated body fluid (SBF) testing has for scaffold evaluation is outlined. In addition, scaffolds’ biocompatibility assessment and degradation studies together with kinetic profiling in SBFs are described. Furthermore, analytical and imaging techniques for scaffold characterization is summarized. In vitro cell-based biocompatibility in SBF-exposed scaffolds and time-resolved degradation studies are shown. Furthermore, limitations and challenges of in vitro SBF testing are discussed. To finish, this chapter concludes with the case studies and applications as well as with emerging trends and the direction to take in the near future.