Emerging need for large-scale, high-resolution analysis of biopolymers, such as DNA sequencing polymerase chain reaction, (PCR) product sizing, single nucleotide polymorphism (SNP) hunting and analysis of protein molecules necessitated the development of automated and high-throughput gel electrophoresis based methods enabling rapid, high-performance separations in a wide molecular weight range. Scaling down electric field mediated separation processes supports higher throughput due to the applicability of higher voltages, thus speeding up analysis time. Indeed, efforts in miniaturization resulted in faster, easier, less costly and more convenient analyses, fulfilling the needs of the emerging biotechnology industry for microscale and massively parallel assays. The two primary approaches in miniaturizing electrophoresis dimensions are the capillary and microslab formats. This latter one evolved towards ultrathin-layer gel electrophoresis which is, except from the thickness of the separation platform, slightly in the upper side of the scale, resulting in considerably easier handling. Ultrathin-layer gel electrophoresis combines the advantages of conventional slab-gel electrophoresis (multilane format) and capillary gel electrophoresis (rapid, high-efficiency separations). It is readily automated, automatic versions of it have been extensively used for large-scale DNA sequencing in the Human Genome Project and more recently became popular in high throughput DNA fragment analysis. Ultrathin-layer techniques are the first step towards the wider use of electrophoresis microchips in perfecting a user-friendly interface between the user and the microdevice.