Enhancement mode GaAs junction field-effect transistors have been explored in their application to digital and linear integrated circuit design. A 3-input NAND-gate and a one stage differential amplifier have been fabricated in integrated form on a 30 × 30 mil 2 chip. The electrical performance characteristics will be described. With a 4 micron gate length the monolithically integrated 3- input NAND-gate has a propagation delay time of 1 ns with a power dissipation of 2mW per gate, i.e., speed-power product of 2 pJ. The differential amplifier has a response time of 2 ns and flat frequency response to about 150 MHz. GaAs enhancement (normally-off) JFET integrated circuits offer better speed-power products than CMOS or Schottky-clamped bipolar ones at operating frequencies of 1 MHz and above. Optimized devices are capable of operating with a speed-power product of 1-2 pJ in the subnano-second switching range. The temperature range from 2°K to 650°K (or 380°C) for GaAs JFET's encompasses applications which are not possible with silicon devices GaAs JFET's and IC's are superior to Si devices and IC's in gamma and neutron environments and offer a potential design in radiation hardened integrated electronics.