The objective of this study is to analyze the dynamics of the Niger riverbed occupationin Niamey. The methodology used is based on the processing of satellite images and their interpretation. The results showed, between 1973 and 2018, a reduction of the free riverbed (from 2415.28 ha in 1973 to 1952.88 ha in 2018 i.e. a regression of 29.91 ha) following its progressive occupation by irrigated crops, dwellings and islands, of about 10.27 ha/year. The islands surface area increase reflects the silting of the river. This silting up causes the river to overflow and worsens flooding.