Measurements and interpretation of ultrasonic velocities in complex media place requirements upon the measurements techniques which cannot be met by conventional ultrasonic equipment. The widely used high resolution echo and pulse overlap techniques are not generally applicable to such materials, especially in composites where the pulse is often severely distorted. A new high time resolution method based upon the pulse transmission technique is described to meet these applications. This approach is well suited to the measurement of ultrasonic velocities and velocity changes in media which are highly dispersive and/or highly attenuating. By using a crossover‐point detecting circuit, time measurements may be made at asinglereference point in the received acoustic pulse with a resolution of better than 1 nsec. If the pulse is distorted, such measurements at more than one crossover‐point are useful in performing a mathematical analysis upon the rf pulse. In single crystal aluminum, where echo measurements can be used for comparison, a timing accuracy of 2 nsec is demonstrated for the technique. Also, the unusually wide frequency capability of the method is demonstrated with measurements of the dispersion curve for high purity polymethylmethacrylate (PMMA).