Stability is an important parameter to evaluate the quality, safety and efficacy of drug substances and pharmaceutical products. The stability studies aim to determine the ability of a formulation to maintain its specifications, in order to establish shelf life and recommended storage conditions. Despite the extensive relevance, until the 1980’s the stability assessment methods complied with technical and scientific principles without the intervention of regulatory acts by health authorities. The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) establishment in the 1990’s boosted the regulation on this issue, not only in the attended countries, but worldwide. In the Brazilian context, the first regulatory norm for stability studies was published in 2002 and it implied the requirement of the submission of a stability report for the sanitary registration of medicines. The development of the Brazilian legislation resulted, among other factors, from the progress of the analytical methods that have become increasingly efficient, sensitive and selective, which allows the achievements of results with greater accuracy and speed; and the use of modern techniques of solid form characterization, which provide important information about the stability of active ingredients and pharmaceutical products.