An integrated microdevice for the analysis of DNA restriction fragments or sequencing fragments is currently being constructed in our laboratory and consists of two principal components: a piezo‐driven micropump and a microelectrophoresis device with integrated fluorescence detector. The syringe pump consisted of a piezoelectric actuator and a pivoted lever for amplification to deliver solvents free from pump pulsations at volumetric flow rates approaching 1 nL/min, even at high loading levels (high output pressures). The flow was programmed by controlling the voltage waveform to the piezo‐actuator to produce a linear displacement of 80 μm and, by using the pivoted lever, a total linear displacement of 650 μm was achieved. The total volume delivered in a single pump stroke was 565 nL. The piezo‐pump was found to adequately deliver stable flow of solutions with loading pressures as high as 3.79×10⁵ Pa (actual loading pressure at the piezo is 3.41×10⁶ Pa). The second component consisted of an electrophoresis device micromachined in polymethylmethacrylate (PMMA) using X‐ray lithography (LIGA). The device was fabricated using a transfer mask technique, in which the channel topography was transferred to a PMMA substrate coated with a positive photoresist and a thin Au/Cr plating base using an optical mask with subsequent X‐ray exposure to produce the desired channel topography. The channels were found to be 20 μm in width (determined by optical mask) with channel depths of 50 μm (determined by X‐ray exposure time) and aspect ratios of approximately 1:10,000, significantly better than those obtained using wet‐chemical etching in glass. The detection apparatus used a fiber optic to deliver the laser light to the electrophoresis device with the emission collected via the same fiber and the wavelength sorting accomplished with a dichroic filter. Since the electroosmotic flow in the PMMA was found to be approximately 5 times smaller compared to glass at typical separation pH for DNA (8.6), the walls of the PMMA device would not require a polymer coating to reduce this flow when performing high‐resolution DNA separations. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 413–422, 1998