The photoacoustic technique, using a piezoelectric transducer to detect acoustic signals induced in semiconductors by the absorption of light, has been used to measure two-photon absorption. The transducer signal amplitude is directly proportional to the absorbed energy from all absorption processes, nonlinear as well as linear. This signal was monitored as a function of the intensity of single, picosecond, 1.06 μm, pulses. At high intensities, beam depletion was observed, and a direct comparison was made with the sample transmission. The sensitivity of this technique allows nonlinear absorption to be measured at intensities significantly lower than when using transmission. In addition, the advantage of the nonlinear photoacoustic technique over the recently described calorimetric technique is that powerful signal averaging techniques can be used. This is because the absorption at a given intensity can be determined by a single pulse in a few microseconds while calorimetry requires at the least several seconds.