Analysis of X band SAR imagery collected during the MARSEN experiment indicates that the APD-10 SAR system imaged both range- and azimuth-traveling gravity waves. However, only the near-edge portion of the APD-10 imagery provided reliable spectral wave estimates. Numerous motion artifacts, which manifest themselves as azimuth-oriented streaks, are visible on the data and are believed to be caused by breaking waves. Because of the large platform velocity, the APD-10 SAR data are relatively insensitive to wave enhancement adjustments performed during the processing of SAR signal histories. A modulation transfer function to relate SAR-derived spectra to in situ measurements has been developed. The transfer function is smaller and falls off more rapidly with wave number for azimuth-traveling waves than for range-traveling waves. This is a consequence of the smaller inherent modulation for the azimuth-traveling waves and the degraded resolution in the azimuth directions as a result of motion effects and agrees, at least qualitatively, with theoretical predictions.