Sample digestion plays an essential role in almost all analytical processes, but is not recognized as an important step in analytical chemistry. In the last period, it is recognize the importance of the sample digestion (wet/dry digestion or decomposition) for the obtaining of high-quality analytical and valid results. The operation is the source of any potential errors: contaminants from the vessels, impurities from the chemical reagents etc. The aim of this paper it is not to discuss or to avoid the systematic errors which appears during the sample digestion in the laboratory. The paper wish to be a pertinent review for a topic analytical technique, namely microwave digestion, like a rapid and productive wet-digestion analysis.