To date, microwave-assisted techniques of sample preparation have found numerous applications in the analysis of forensic and clinical samples. Microwave-assisted mineralization is currently one of the fundamental techniques for digestion of the biological matrix in elemental analysis. Its major advantages include a short time of sample preparation, low cost and good availability of commercial instruments. The number of scientific papers concerning application of microwave assisted extraction is systematically growing. It is assumed that in the near future microwave-assisted techniques will be routinely used in analytical laboratories, including ones dealing with forensic and clinical analysis. Due to the increasing potential of contemporary analytical methods used in forensic analysis, as well as higher requirements and expectations, sample preparation has become extremely important. For several years, microwave-assisted techniques have played a significant role in sample preparation for chemical analysis. In this paper, the theoretical background of microwave-assisted processes has been presented and applications of microwave energy to mineralization and extraction, especially in the preparation of forensic and clinical samples, have been reviewed. Tables and references