The subsidence rate in a reclaimed coastal land has been estimated using JERS-1 L-band SAR two-pass differential interferometry (DInSAR). Owing to the severe temporal decorrelation induced by frequent soil loading and to the intense deformation gradient, the L-band was effective for observation of subsidence in the reclaimed land. Permanent scatterers were also used to remove residual phase. We evaluated the accuracy of the estimated subsidence rate using field measurements obtained by magnetic probe extensometer with an accuracy of /spl plusmn/1 mm from 42 ground stations. Two-dimensional subsidence map was achieved from 5 qualified interferograms. The correlation coefficient between the two-dimensional radar measurements and the in situ data was 0.87 with an r.m.s. error of 1.44 cm. The results demonstrate that L-band DInSAR is useful for geological engineering applications.