Cadmium arsenide is a II-V semiconductor which exhibits n-type intrinsic conductivity with high mobility up to mu(u) = 1.0-1.5 m(2)/V s. Potential applications include magnetoresistors and both thermal and photodetectors, which require electrical characterization over a wide range of deposition and measurement conditions. The films were prepared by vacuum evaporation with deposition rates in the range 0.5-6.0 nm/s and substrate temperatures maintained at constant values of 20-120 degrees C. Sandwich-type samples were deposited with film thicknesses of 0.1-1.1 mu m using evaporated electrodes of Ag and occasionally Au or Al. Above a typical electric field F-b of up to 5 x 10(7) V/m all samples showed instabilities characteristic of dielectric breakdown ol electroforming. Below this field they showed a high-field conduction process with logJ proportional to V-1/2, where J is the current density and V the applied voltage. This type of dependence is indicative of carrier excitation over a potential barrier whose effective barrier height has been lowered by the high electric field. The field-lowering coefficient beta had a value of (1.2-5.3) x 10(-5) eV m(1/2)/V-1/2 which is reasonably consistent with the theoretical value of beta(PF) = 2.19 x 10(-5) eV m(1/2)/V-1/2 expected when the field-lowering occurs at donor-like centres in the semiconductor (Poole-Frenkel effect). For thinner films Schottky emission was more probable. The effects of the film thickness, electrode materials, deposition rate, and substrate temperature on the conductivity behaviour are discussed.