A pulsed GaAs laser rangefinder is analyzed and designed. Expressions for background and signal power, noise, and signal-to-noise ratio are derived. The effects of pulse rise time, receiver bandwidth, and SNR on probability of detection and range accuracy are discussed. A computer simulation is used to optimize laser power, receiver aperture, and preamplifier bandwidth. A method ofthreshold detection is presented and discussed. Experimental results include receiver preamplifier transfer function and threshold detector performance.