A stable streamlining trend in the field of medical diagnostics by practical adoption of high-tech and knowledge-intensive analytical systems providing for molecular level studies has appeared during the last few decades. An illustrative example of such technologies is mass spectrometry methods for analyzing biomolecules. This review is intended to brief the potential of the state-of-the-art inventory of spectrometry equipment and illustrate the application of mass spectrometry of nucleic acids (DNA and RNA) for solving practical problems related to the analysis of human genomic DNA and clinically significant microorganisms of bacterial and viral natures.