This study aims to compare the socio-spatial changes in Brazzaville and Pointe-Noire over three periods: 1980, 2000 and 2023. The methodology is based on documentary research, remote sensing and GIS, using colour composition (RGB infrared), supervised classification based on the kappa method and validation of results on ArcGIS. The results show that both cities have experienced significant urban expansion, driven by sustained population growth. In Brazzaville, the population grew from 300,183 inhabitants in 1974 to 2,145,783 inhabitants in 2023, compared to 140,378 inhabitants to 1,420,162 inhabitants for Pointe-Noire over the same period. This population growth has led to unregulated urban sprawl, encouraging the proliferation of informal settlements and engulfing nearby rural areas. The urban area has grown from 508.68 ha in 1980 to 824.046 ha in 2000, reaching 1,695.582 ha in 2023 in Brazzaville, compared to 486.132 ha, 643.746 ha and 1,142.802 ha in Pointe-Noire over the three periods. Urban infrastructure has not kept pace with growth, leading to deficits in basic services. There are similar trajectories of rapid but poorly controlled urbanisation, with significant environmental and social impacts. This calls for better urban planning with a view to sustainable and inclusive cities.