The conventional quadrupole mass spectrometer (QMS) arrangement uses circular metallic rods as the mass filter excited electrically at voltages up to 1 kV depending upon the application. If the size and voltages can be reduced then the range of applications for QMS instruments would increase. The application of microelectromechanical systems (MEMS) technology allows the fabrication of submillimeter versions of such structures. In this article the development of a miniature QMS is reported in which the conventional rod arrangement has been replaced with a microengineered version. The structure is made in silicon with metallized specially drawn glass fibers of length 20-30 mm and diameter 0.5 mm to act as the quadrupole rods. This is about one order of magnitude smaller than most conventional QMS filters, with the potential for further reduction in size. The MEMS mass filter was mounted onto a commercial ion source, which was in turn attached to a vacuum flange and supplied by an electronic drive circuit at 6 MHz. Mass spectra in the range 0-50 amu for a range of operating conditions have been obtained indicating a linear mass scale and a best resolution at 10% peak height of around 30. The use of pole bias applied to the rods is shown to be beneficial. Reliable QMS operation was obtained up to a pressure of 10(-2) mbar.