Scanning synthetic aperture radar (ScanSAR) interferometry using full-aperture approach has been used in the geophysical community when a standard ScanSAR interferometric processor is not available. Although interferograms can routinely be produced as well, some concerns about the full-aperture processing still remain. In this letter, we assess the quality of the interferogram produced by this approach. After theoretical analyses, we compare interferograms produced by the full-aperture approach and the standard burst-by-burst approach. Comparison results show that the difference between the final interferograms produced by the two approaches is small. For the data processed, the mean value and standard deviation of the difference phase are 8.36 ×10^-4 rad and 3.60 ×10^-1 rad, respectively. These results confirm the availability of full-aperture processing for most of the geophysical applications using ScanSAR interferometry.