Abstract Topography is the dominant factor in the SLAR-image of a hilly area. To analyze soil moisture condition by interpretation of this imagery, a first step is to estimate the influence of topography on microwave backscatter. With a digital terrain illumination model, a SLAR image can be simulated. This was done by modeling 50 m × 50 m grid elements of a 3.2 km 2 catchment. Comparison of the corresponding model and SLAR-image grid elements revealed a quite good correlation. The remaining variation is to a large degree explained by soil moisture changes in the catchment area. When two extremely different moisture conditions were compared the sensitivity of microwave backscatter to decreasing incidence angle was obvious. Presentation of the spatial distribution of soil moisture was prevented by insufficient spatial resolution for the very heterogeneous catchment.